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Botanical Name: Allium sativum L.
Pharmacopoeial Name: Alii sativi bulbus.
Synonym: Porvium sativum Rehb.
Common Names: Garlic, stinking rose.

Summary Table
Drug/Class Interaction TypeMechanism and SignificanceManagement
Potential pharmacokinetic interaction caused by garlic inhibition of cytochrome P450 2E1 may reduce hepatoxic metabolite NAPQI formation. Not clinically demonstrated.Not applicable for management of acute acetaminophen toxicity.
Antiplatelet thromboprophylactics
/ /
Possible additive increased antiplatelet activity with dipyridamole. Not established with other antiplatelet agents.
Clinical significance not established; increased risk of bleeds likely overstated.
Avoid or adopt and monitor bleed times.
Combine garlic in antithrombotic protocols.
Anthracycline chemotherapy
Garlic protects against and reduces drug-induced cardiotoxicity through multiple mechanisms, including increasing myocardial antioxidant status. Not clinically demonstrated.Pretreat, coadminister, and continue herb postchemotherapy in cardioprotective protocols.
HMG-CoA reductase inhibitors (statins)
Additive inhibition of HMG-CoA theoretically allows lowered statin dose and reduction of drug adverse effects. Plausible but not clinically established.Consider adopting if statin-induced ADRs (myalgias, fatigue, etc.); trial if symptomatic.
Fluorouracil (5-FU)
Chemotherapy associated with mucositis
Garlic may prevent and reduce chemotherapy-induced mucositis through anti-inflammatory and antioxidant mechanisms. Not clinically established.Consider incorporating garlic with other agents in protective protocols for chemotherapy-induced mucositis.
Protease inhibitor antiretrovirals
Possible pharmacokinetic interaction with saquinavir; reduces drug bioavailability; does not occur with ritonavir. Unknown significance and applicability to related protease inhibitors.Monitoring serum drug levels advisable if coadministered.
Oral vitamin K antagonist anticoagulants
Theoretical additive effects on hemostasis caused by possible platelet inhibition. Clinical studies suggest interaction insignificant.If coadministered, monitor INR and check for peripheral bleed symptoms.
HMG-CoA , Hydroxymethylglutaryl coenzyme A; ADRs , adverse drug reactions; INR , international normalized ratio.
herb description



Related Species

Allium cepa L. (onion), Allium schoenoprasum L. (chives).

Habitat and Cultivation

Originally native to central Asia; commercially cultivated for 5000 years as a food and medicinal herb worldwide.

Parts Used

Fresh or dried bulb.

Common Forms

  • Fresh bulb.
  • Dried bulb.
  • Dried powder (allicin-stabilized).
  • Aged garlic extract (AGE).
  • Garlic oil (steam-distilled).
  • Garlic oil (macerated).

herb in clinical practice


Garlic dietary supplements consistently occupy second or third place of the top-selling botanical products in the United States, quite apart from the widespread availability and use of garlic cloves as a dietary/culinary herbal ingredient. Scientific studies and numerous clinical trials support the following three primary areas of use in modern practice:

  1. For cardiovascular disease prevention and treatment as a hypolipidemic, antiatherosclerotic, hypotensive, antiplatelet, and fibrinolytic agent.
  2. For infectious conditions as a broad-spectrum antibiotic, antifungal, antiviral, and anthelmintic agent.
  3. As a chemopreventive and anticancer agent; antioxidant and immunostimulant properties impact each of these areas.

    The pharmacology of the herb derives from its organosulfur constituents (OSCs), although the chemistry of these is extremely complex and has not been fully characterized. Importantly, different garlic preparations may have significantly different constituent profiles; the principal compounds in the intact bulb are gamma-glutamyl cysteine peptides and the cysteine sulfoxide alliin. The enzyme allinase (released by damage to intact cells) converts alliin to the thiosulfinate allicin. Allicin is unstable and degrades to various volatile sulfide congeners, depending on the conditions applied. Steam distillation converts water-soluble thiosulfinates to oil-soluble diallyl sulfides, whereas oil maceration produces ajoenes and vinyldithins.

    Similarly, pharmacokinetic differences exist among the various preparations and their components. Metabolic transformation of various sulfides leads to the formation of compounds that have modulating effects on the cytochrome P450 (CYP450) system. Enteric-coated preparations have been shown to release only a fraction of their active allicin content.

    These differences complicate attempts to compare data from various experimental and clinical trials using different garlic preparations. More than 45 randomized clinical trials have been conducted with garlic preparations. Metastudies have concluded that these trials show positive, although limited, short-term benefits of garlic on serum cholesterol and some coagulation parameters, but no significant effect on hypertension or blood glucose levels. 1-4Some authors have criticized the meta-analyses, noting the lack of equivalence between preparations and inadequate definition or characterization of active principles in the trials, which seriously limits the clinical conclusions that can be drawn from the majority of trials to date. 5,6Epidemiological studies of the cancer-protective effects of garlic consumption have also been subject to meta-analysis, and positive effects were found for stomach and colon cancers from raw and cooked garlic consumption. 7,8

    Garlic has not been official in the U.S. Pharmacopoeia since 1900, but it is listed in the 2002 edition of the National Formulary as “fresh or dried compound bulbs containing not less than 0.5% alliin.” The German Commission E approved the use of “fresh or carefully dried bulbs” as “supportive to dietary measures at elevated levels of lipids in the blood” and as a “preventative for age-dependent vascular changes.” 9 The European Scientific Cooperative on Phytotherapy (ESCOP) monograph indicates garlic for “treatment of elevated blood lipid levels insufficiently influenced by diet” and mentions the traditional indication for upper respiratory tract infections and catarrhal conditions while also noting that these lack trial support. 10 The World Health Organization (WHO) also includes mild hypertension as an indication. 11 Both ESCOP and McKenna et al. 12 provide comprehensive reviews of the recent scientific literature.

    Historical/Ethnomedicine Precedent

    In Europe, garlic has been used for millenia. It was a staple of the Roman army, Pliny recorded more than 60 uses for garlic, and Galen first recorded its use as a disinfectant before and after surgery. More recent folk use centers on respiratory conditions, including coughs, colds, flus, sinus and bronchial infections, pneumonia and tuberculosis, and the elimination of worms and other parasites. As an external treatment, garlic has been used as a “counterirritant” for rheumatic and arthritic conditions, as well as for earache, skin infections, and snakebites. Topical applications are also used in respiratory conditions. Garlic has been employed in all major world systems of medicine for many years. In China, garlic use was recorded in texts from the fifth centuryCE, principally as an antidote for poisons as well as a treatment for infectious and parasitical intestinal conditions such as diarrhea, dysentery, and diphtheria.

    Known or Potential Therapeutic Uses

    Antimicrobial, antifungal, atherosclerosis, bronchial and upper respiratory conditions, catarrh, colds, coughs, flu, gastric and colon carcinomas (prevention), hyperlipidemia, hypertension, hyperviscosity, immunostimulation, peripheral arterial occlusive disease, rhinitis, sinusitis, thrombosis.

    Key Constituents

    Organosulfur compounds (OSCs), principally alliin [(+)- S-allyl-L-cysteine sulfoxide] and gamma-L-glutamyl peptides. Alliin is transformed into allicin by allinase, and depending on physicochemical conditions, various derivatives may be formed. Flavonoids and saponins are also present.

    Therapeutic Dosing Range

    • Fresh Garlic: 2.7 to 4.0 g daily.
    • Dried Powder: 0.4 to 1.2 g daily.
    • Tincture (1:5): 20 mL daily.
    • Oil: 2 to 5 mg daily.
    • Standardized Extracts:
      • Garlic powder (Kwai): 200 to 300 mg three times daily.
      • Aged garlic extract (AGE, Kyolic): 300 to 800 mg three times daily.
      • Other preparations: Corresponding to 4 to 12 mg alliin, or 2 to 5 mg allicin-equivalent daily.

interactions review

Strategic Considerations

The German Commission E did not list any known interactions for garlic in its 1998 monograph. 9 However, the later monographs by WHO and ESCOP both list a possible interaction between garlic and warfarin. 10,11Although garlic consumption is usually assumed to be a risk to anticoagulated patients, reliable reports of such interactions are not available. 13

As with ginkgo, garlic and several of its constituents have established antiplatelet activity in vitro. Using aggregometry in response to platelet-stimulating factors such as collagen and adenosine diphosphate (ADP), three clinical trials have demonstrated modest effects on platelet aggregation in vivo by AGE extracts 14,15and garlic powder. 16,17Bleed times and international normalized ratio (INR) were not measured, and the clinical significance of the antiaggregatory effects of garlic remains to be established. Three reports associate garlic alone with spontaneous bleeding, but none of these allows causality to be attributed to the herb 18-20(see later discussion on garlic and antiplatelet thromboprophylactics). Cessation of high levels of garlic consumption before elective surgery may be prudent, but on the basis of currently available evidence, the risk of garlic-induced bleeding and interactions with drugs affecting hemostasis appears to be very low. 21

On the other hand, inclusion of garlic in protocols for patients at risk of thrombosis, particularly those with history of atherosclerotic disease, offers multiple “collateral” benefits due to the pleiotropic actions of the herb on several cardiac risk factors. 22-27The lipid-lowering effect of garlic extracts operates by several mechanisms, including the inactivation of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase. This has led at least one author to suggest the potential value of combining garlic with pharmaceutical HMG-CoA reductase inhibitors for hyperlipidemia to reduce the risk of adverse effects such as rhabdomyolysis in sensitive populations, such as renal transplant patients. 28 This potentially beneficial interaction is proposed later, although previously undefined in the literature.

Effects on Drug Metabolism and Bioavailability

Experimental, animal, in vitro, and ex vivo human data suggest that garlic OSCs may be substrates, inducers, and/or inhibitors of various CYP450 enzymes. As with the pharmacodynamic effects of garlic, there are differences in effect among the different OSCs, different dose/duration regimens, and different species (mouse, rat, rabbit, human). The full spectrum of effects of OSCs on drug metabolism in humans is not well understood, but in vivo evidence is compelling for an inhibition of CYP450 2E1 by OSCs.

Diallyl sulfide (DAS) is converted by CYP2E1 to diallyl sulfoxide (DASO) and sequentially to diallyl sulfone (DASO2). 29 These derivatives are competitive inhibitors of 2E1, and DASO2is also an irreversible (suicide) inhibitor of 2E1. 30,31This is a typical example of 2E1 activity, which shares with CYP450 1A1 and 1A2 the role of metabolizing potentially carcinogenic aromatic hydrocarbons, and which may also bioactivate certain substrates to toxic or reactive intermediates (e.g., acetaminophen; see later discussion). 32,33Loizou and Cocker 34 found that both DAS and garlic oil extract showed significant inhibition of 2E1 in eight healthy human volunteers with the 2E1 probe chlorzoxazone. Gurley et al. 35 also found significant inhibition of 2E1 after 28 days of garlic oil administration in healthy human volunteers using the same chlorzoxazone probe methodology. Davenport and Wargovich 36 found that single-dose in vivo OSCs in a rodent model decreased 2E1 protein but not its messenger ribonucleic acid (mRNA) levels. They also noted a slight increase in 1A1 and 1A2 levels.

Inhibition of CYP450 2E1 is considered one of the major mechanisms by which garlic consumption reduces mutagenesis and carcinogenesis and exerts hepatoprotective effects. 37,38Other mechanisms may be involved, including OSC induction of glutathione transferases as well as scavenging of carcinogenic free-radical species. 39,40Recent studies suggest that a number of complex effects on signal-transduction pathways may be involved in the chemopreventive effects of garlic OSCs. 41 Garlic-drug interactions with 2E1 substrates caused by inhibition by garlic OSCs have not yet appeared to be a clinically significant issue, and case reports are lacking. Drug substrates that theoretically may be affected by inhibition of 2E1 are verapamil, the halogenated anesthetics, and (a minor pathway) theophylline. In a clinical study restricted to older volunteers (mean age, 67 years), Gurley et al. 42 found a 22% inhibition of 2E1 by garlic oil administered for 28 days. The authors suggested that age-related changes in CYP450 activity are significant and should be factored into drug dose and potential interactions calculations.

Garlic is not the only dietary substance to modulate 2E1 expression. Inducers include ethanol, lettuce, and above all, increased body weight or obesity, whereas inhibitors include watercress and elements of Camellia sinensis (both green tea and black tea), especially epigallocatechin-3-gallate. If polymorphisms are taken into account, the total contribution of these variables to individual response variation in 2E1-mediated clearance of the probe substrate chlorzoxazone is 73%, with body weight alone accounting for 43% of the phenotypical variability in 2E1 activity. 43,44

The effect of garlic on CYP450 enzymes other than 2E1 is less clear. A “before and after” probe study with healthy volunteers examined the effect of Kwai (aged) garlic consumption (600 mg three times daily for 14 days) on probe drugs for CYP3A4 (alprazolam) and CYP2D6 (dextromethorphan) pharmacokinetics and found no significant effects after garlic administration. 45 The authors concluded that aged (Kwai) garlic is unlikely to cause 3A4-modulated or 2D6-modulated drug interactions. Gurley et al. 35 found no effect of garlic oil on 3A4, 2D6, or 1A2 in healthy volunteers using a midazolam, debrisoquin, and caffeine cocktail in the study previously mentioned that demonstrated 2E1 inhibition.

Foster et al. 46 conducted an in vitro study using recombinant human CYP450 enzymes that investigated the effects of 10 different garlic products (including aged, odorless, oil, freeze-dried, and three fresh forms: common, Chinese, and elephant) on enzyme activity. The authors found that 2D6 was unaffected, but that 2C9*1, 2C19, 3A4, 3A5, and 3A7 were all inhibited by fresh garlic, whereas 2C9*2 was actively stimulated by fresh garlic. These authors concluded that pharmacokinetic interactions with narrow-therapeutic-range drugs may result from garlic consumption, affecting metabolism of drug substrates mediated by 2C9, 2D6, and 3A4. The same extracts were tested against an in vitro model of P-glycoprotein (P-gp) based on an adenosinetriphosphatase (ATPase) colorimetric assay, using verapamil as a positive control. (Stimulation of the ATPase assay is correlated with increased inhibitory activity of P-gps.) Aqueous extracts of aged garlic preparations exerted a very low to moderate inhibition of P-gp in the assay used. 46 In another in vitro model based on human KB-C2 cells, Nabekura et al. 47 found no effect of OSCs on the P-gp–mediated transport of daunorubicin and rhodamine 123. Greenblatt et al. 48 used an in vitro human hepatocyte model to test possible activity of different water-soluble compounds in garlic for CYP inhibitory activity and found negligible effect, except for high concentrations (100 µmol/L) of S-methyl-L-cysteine and S-allyl-L-cysteine, both of which produced modest inhibition of CYP3A. The authors concluded that CYP3A interactions with garlic and prescription drugs were unlikely.

Pharmacokinetic data for garlic (other than those related to drug-metabolizing systems) are minimal. However, one rodent study examined the effect of the saponin constituents of garlic and concluded that these compounds may contribute to the lipid-lowering activity of garlic by reducing lipid absorption levels at the intestinal wall. 49 Studies are required to delineate human pharmacokinetics of garlic and OSC preparations in order to determine the extent to which many of the important effects of OSCs described in vitro in animal models can be replicated in vivo at micromolar concentrations that correspond to those employed in the experimental models. Further research is also required to establish the full spectrum of effects of different forms of garlic and OSCs on drug metabolism and potential pharmacokinetic interactions. Inconclusive data are available relating to garlic and the human immunodeficiency virus type 1 (HIV-1) protease inhibitors, saquinavir and ritonavir (discussed later). Patients with HIV infection are likely to take garlic products or preparations, and physicians specializing in this patient population are usually aware of the complexities of managing polypharmaceutical regimens and empirically monitoring possible interactions. Other than this clinically circumscribed area, currently no compelling data exist on adverse pharmacokinetic interactions between pharmaceuticals and garlic preparations. The established inhibition of CYP450 2E1 underlies a major part of the hepatoprotective and chemoprotective benefits of garlic consumption.

herb-drug interactions
Dipyridamole and Related Antiplatelet Thromboprophylactics
Doxorubicin and Related Anthracycline Chemotherapy Agents
Hydroxymethylglutaryl Coenzyme A (HMG-CoA) Reductase Inhibitors (Statins)
Mucositis-Inducing Chemotherapeutic Agents, Including Fluorouracil, Bleomycin, Doxorubicin, and Ethanol
Saquinavir and Related Antiretroviral Protease Inhibitors
Warfarin and Related Oral Vitamin K Antagonist Anticoagulants
theoretical, speculative, and preliminary interactions research, including overstated interactions claims
Oral Hypoglycemic Agents and Insulin
  • 1.Warshafsky S, Kamer RS, Sivak SL. Effect of garlic on total serum cholesterol: a meta-analysis. Ann Intern Med 1993;119:599-605.View Abstract
  • 2.Ackermann RT, Mulrow CD, Ramirez G et al. Garlic shows promise for improving some cardiovascular risk factors. Arch Intern Med 2001;161:813-824.
  • 3.Stevinson C, Pittler MH, Ernst E. Garlic for treating hypercholesterolemia: a meta-analysis of randomized clinical trials. Ann Intern Med 2000;133:420-429.View Abstract
  • 4.Silagy C, Neil A. Garlic as a lipid lowering agent—a meta-analysis. J R Coll Physicians Lond 1994;28:39-45.View Abstract
  • 5.Lawson LD, Wang ZJ, Papadimitriou D. Allicin release under simulated gastrointestinal conditions from garlic powder tablets employed in clinical trials on serum cholesterol. Planta Med 2001;67:13-18.View Abstract
  • 6.Lawson LD, Wang ZJ. Low allicin release from garlic supplements: a major problem due to the sensitivities of alliinase activity. J Agric Food Chem 2001;49:2592-2599.View Abstract
  • 7.Fleischauer AT, Poole C, Arab L. Garlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers. Am J Clin Nutr 2000;72:1047-1052.View Abstract
  • 8.El-Bayoumy K, Sinha R, Pinto JT, Rivlin RS. Cancer chemoprevention by garlic and garlic-containing sulfur and selenium compounds. J Nutr 2006;136:864S-869S.View Abstract
  • 9.Blumenthal M, Busse W, Goldberg A et al. The Complete German Commission E Monographs. Austin, Texas: American Botanical Council: Integrative Medicine Communications; 1998.
  • 10.ESCOP. Allii Sativi Bulbus. ESCOP Monographs: the Scientific Foundation for Herbal Medicinal Products. 2nd ed. Exeter, UK: European Scientific Cooperative on Phytotherapy and Thieme; 2003:14-25.
  • 11.WHO. Bulbus Allii Sativi. WHO Monographs on Selected Medicinal Plants. 1 vol. Geneva: World Health Organization; 1999:16-33.
  • 12.McKenna D, Jones K, Hughes K, Humphrey S. Garlic. Botanical Medicines. 2nd ed. Binghampton: Haworth Press; 2002:375-409.
  • 13.Vaes LP, Chyka PA. Interactions of warfarin with garlic, ginger, ginkgo, or ginseng: nature of the evidence. Ann Pharmacother 2000;34:1478-1482.View Abstract
  • 14.Steiner M, Li W. Aged garlic extract, a modulator of cardiovascular risk factors: a dose-finding study on the effects of AGE on platelet functions. J Nutr 2001;131:980S-984S.View Abstract
  • 15.Rahman K, Billington D. Dietary supplementation with aged garlic extract inhibits ADP-induced platelet aggregation in humans. J Nutr 2000;130:2662-2665.View Abstract
  • 16.Kiesewetter H, Jung F, Pindur G et al. Effect of garlic on thrombocyte aggregation, microcirculation, and other risk factors. Int J Clin Pharmacol Ther Toxicol 1991;29:151-155.View Abstract
  • 17.Kiesewetter H, Jung F, Jung EM et al. Effect of garlic on platelet aggregation in patients with increased risk of juvenile ischaemic attack. Eur J Clin Pharmacol 1993;45:333-336.View Abstract
  • 18.German K, Kumar U, Blackford HN. Garlic and the risk of TURP bleeding. Br J Urol 1995;76:518.View Abstract
  • 19.Rose KD, Croissant PD, Parliament CF, Levin MB. Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: a case report. Neurosurgery 1990;26:880-882.View Abstract
  • 20.Burnham BE. Garlic as a possible risk for postoperative bleeding. Plast Reconstr Surg 1995;95:213.View Abstract
  • 21.Macan H, Uykimpang R, Alconcel M et al. Aged garlic extract may be safe for patients on warfarin therapy. J Nutr 2006;136:793S-795S.View Abstract
  • 22.Siegel G, Walter A, Engel S et al. [Pleiotropic effects of garlic]. Wien Med Wochenschr 1999;149:217-224.View Abstract
  • 23.Thomson M, Al-Qattan KK, Bordia T, Ali M. Including garlic in the diet may help lower blood glucose, cholesterol, and triglycerides. J Nutr 2006;136:800S-802S.View Abstract
  • 24.Budoff M. Aged garlic extract retards progression of coronary artery calcification. J Nutr 2006;136:741S-744S.View Abstract
  • 25.Yeh YY, Yeh SM. Homocysteine-lowering action is another potential cardiovascular protective factor of aged garlic extract. J Nutr 2006;136:745S-749S.View Abstract
  • 26.Weiss N, Ide N, Abahji T et al. Aged garlic extract improves homocysteine-induced endothelial dysfunction in macro- and microcirculation. J Nutr 2006;136:750S-754S.View Abstract
  • 27.Borek C. Garlic reduces dementia and heart-disease risk. J Nutr 2006;136:810S-812S.View Abstract
  • 28.Lash JP, Cardoso LR, Mesler PM et al. The effect of garlic on hypercholesterolemia in renal transplant patients. Transplant Proc 1998;30:189-191.View Abstract
  • 29.Teyssier C, Guenot L, Suschetet M, Siess MH. Metabolism of diallyl disulfide by human liver microsomal cytochromes P-450 and flavin-containing monooxygenases. Drug Metab Dispos 1999;27:835-841.View Abstract
  • 30.Jin L, Baillie TA. Metabolism of the chemoprotective agent diallyl sulfide to glutathione conjugates in rats. Chem Res Toxicol 1997;10:318-327.View Abstract
  • 31.Wargovich MJ. Diallylsulfide and allylmethylsulfide are uniquely effective among organosulfur compounds in inhibiting CYP2E1 protein in animal models. J Nutr 2006;136:832S-834S.
  • 32.Tanaka E, Terada M, Misawa S. Cytochrome P450 2E1: its clinical and toxicological role. J Clin Pharm Ther 2000;25:165-175.View Abstract
  • 33.Zhou S, Koh HL, Gao Y et al. Herbal bioactivation: the good, the bad and the ugly. Life Sci 2004;74:935-968.View Abstract
  • 34.Loizou GD, Cocker J. The effects of alcohol and diallyl sulphide on CYP2E1 activity in humans: a phenotyping study using chlorzoxazone. Hum Exp Toxicol 2001;20:321-327.
  • 35.Gurley BJ, Gardner SF, Hubbard MA et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-287.View Abstract
  • 36.Davenport D, Wargovich M. Modulation of cytochrome P450 enzymes by organosulfur compounds from garlic. Food Chem Toxicol 2005.View Abstract
  • 37.Yang CS, Chhabra SK, Hong JY, Smith TJ. Mechanisms of inhibition of chemical toxicity and carcinogenesis by diallyl sulfide (DAS) and related compounds from garlic. J Nutr 2001;131:1041S-1045S.View Abstract
  • 38.Taubert D, Glockner R, Muller D, Schomig E. The garlic ingredient diallyl sulfide inhibits cytochrome P450 2E1 dependent bioactivation of acrylamide to glycidamide. Toxicol Lett 2006;164:1-5.View Abstract
  • 39.Wang EJ, Li Y, Lin M et al. Protective effects of garlic and related organosulfur compounds on acetaminophen-induced hepatotoxicity in mice. Toxicol Appl Pharmacol 1996;136:146-154.View Abstract
  • 40.Milner JA. Preclinical perspectives on garlic and cancer. J Nutr 2006;136:827S-831S.View Abstract
  • 41.Herman-Antosiewicz A, Singh SV. Signal transduction pathways leading to cell cycle arrest and apoptosis induction in cancer cells by Allium vegetable-derived organosulfur compounds: a review. Mutat Res 2004;555:121-131.View Abstract
  • 42.Gurley BJ, Gardner SF, Hubbard MA et al. Clinical assessment of effects of botanical supplementation on cytochrome P450 phenotypes in the elderly: St John’s wort, garlic oil, Panax ginseng and Ginkgo biloba. Drugs Aging 2005;22:525-539.
  • 43.Marchand LL, Wilkinson GR, Wilkens LR. Genetic and dietary predictors of CYP2E1 activity: a phenotyping study in Hawaii Japanese using chlorzoxazone. Cancer Epidemiol Biomarkers Prev 1999;8:495-500.
  • 44.Milner JA. Molecular targets for bioactive food components. J Nutr 2004;134:2492S-2498S.View Abstract
  • 45.Markowitz JS, Devane CL, Chavin KD et al. Effects of garlic (Allium sativum L.) supplementation on cytochrome P450 2D6 and 3A4 activity in healthy volunteers. Clin Pharmacol Ther 2003;74:170-177.View Abstract
  • 46.Foster BC, Foster MS, Vandenhoek S et al. An in vitro evaluation of human cytochrome P450 3A4 and P-glycoprotein inhibition by garlic. J Pharm Pharm Sci 2001;4:176-184.View Abstract
  • 47.Nabekura T, Kamiyama S, Kitagawa S. Effects of dietary chemopreventive phytochemicals on P-glycoprotein function. Biochem Biophys Res Commun 2005;327:866-870.View Abstract
  • 48.Greenblatt DJ, Leigh-Pemberton RA, von Moltke LL. In vitro interactions of water-soluble garlic components with human cytochromes p450. J Nutr 2006;136:806S-809S.View Abstract
  • 49.Matsuura H. Saponins in garlic as modifiers of the risk of cardiovascular disease. J Nutr 2001;131:1000S-1005S.View Abstract
  • 50.Manyike PT, Kharasch ED, Kalhorn TF, Slattery JT. Contribution of CYP2E1 and CYP3A to acetaminophen reactive metabolite formation. Clin Pharmacol Ther 2000;67:275-282.
  • 51.Dooley TP. Molecular biology of the human phenol sulfotransferase gene family. J Exp Zool 1998;282:223-230.View Abstract
  • 52.Court MH, Duan SX, von Moltke LL et al. Interindividual variability in acetaminophen glucuronidation by human liver microsomes: identification of relevant acetaminophen UDP-glucuronosyltransferase isoforms. J Pharmacol Exp Ther 2001;299:998-1006.View Abstract
  • 53.Bernal W. Changing patterns of causation and the use of transplantation in the United Kingdom. Semin Liver Dis 2003;23:227-237.View Abstract
  • 54.Lee WM. Acute liver failure in the United States. Semin Liver Dis 2003;23:217-226.View Abstract
  • 55.Hu JJ, Yoo JS, Lin M et al. Protective effects of diallyl sulfide on acetaminophen-induced toxicities. Food Chem Toxicol 1996;34:963-969.View Abstract
  • 56.Hattori A, Yamada N, Nishikawa T et al. Protective effect of ajoene on acetaminophen-induced hepatic injury in mice. Biosci Biotechnol Biochem 2001;65:2555-2557.View Abstract
  • 57.Sumioka I, Matsura T, Yamada K. Therapeutic effect of S-allylmercaptocysteine on acetaminophen-induced liver injury in mice. Eur J Pharmacol 2001;433:177-185.View Abstract
  • 58.Sumioka I, Matsura T, Kasuga S et al. Mechanisms of protection by S-allylmercaptocysteine against acetaminophen-induced liver injury in mice. Jpn J Pharmacol 1998;78:199-207.View Abstract
  • 59.Lin MC, Wang EJ, Patten C et al. Protective effect of diallyl sulfone against acetaminophen-induced hepatotoxicity in mice. J Biochem Toxicol 1996;11:11-20.View Abstract
  • 60.Zhao C, Shichi H. Prevention of acetaminophen-induced cataract by a combination of diallyl disulfide and N-acetylcysteine. J Ocul Pharmacol Ther 1998;14:345-355.View Abstract
  • 61.Kalantari H, Salehi M. The protective effect of garlic oil on hepatotoxicity induced by acetaminophen in mice and comparison with N-acetylcysteine. Saudi Med J 2001;22:1080-1084.View Abstract
  • 62.Gwilt PR, Lear CL, Tempero MA et al. The effect of garlic extract on human metabolism of acetaminophen. Cancer Epidemiol Biomarkers Prev 1994;3:155-160.View Abstract
  • 63.Briggs WH, Xiao H, Parkin KL et al. Differential inhibition of human platelet aggregation by selected Allium thiosulfinates. J Agric Food Chem 2000;48:5731-5735.View Abstract
  • 64.Ali M, Bordia T, Mustafa T. Effect of raw versus boiled aqueous extract of garlic and onion on platelet aggregation. Prostaglandins Leukot Essent Fatty Acids 1999;60:43-47.View Abstract
  • 65.Apitz-Castro R, Badimon JJ, Badimon L. Effect of ajoene, the major antiplatelet compound from garlic, on platelet thrombus formation. Thromb Res 1992;68:145-155.View Abstract
  • 66.Apitz-Castro R, Badimon JJ, Badimon L. A garlic derivative, ajoene, inhibits platelet deposition on severely damaged vessel wall in an in vivo porcine experimental model. Thromb Res 1994;75:243-249.View Abstract
  • 67.Ariga T, Tsuji K, Seki T et al. Antithrombotic and antineoplastic effects of phyto-organosulfur compounds. BioFactors 2000;13:251-255.
  • 68.Chan K-c, Hsu C-c, Yin M-c. Protective effect of three diallyl sulphides against glucose-induced erythrocyte and platelet oxidation, and ADP-induced platelet aggregation. Thromb Res 2002;108:317-322.View Abstract
  • 69.Qi R, Liao F, Inoue K et al. Inhibition by diallyl trisulfide, a garlic component, of intracellular Ca(2+) mobilization without affecting inositol-1,4, 5-trisphosphate (IP[3]) formation in activated platelets. Biochem Pharmacol 2000;60:1475-1483.
  • 70.Rendu F, Brohard-Bohn B, Pain S et al. Thiosulfinates inhibit platelet aggregation and microparticle shedding at a calpain-dependent step. Thromb Haemost 2001;86:1284-1291.View Abstract
  • 71.Allison GL, Lowe GM, Rahman K. Aged garlic extract and its constituents inhibit platelet aggregation through multiple mechanisms. J Nutr 2006;136:782S-788S.View Abstract
  • 72.Allison GL, Lowe GM, Rahman K. Aged garlic extract may inhibit aggregation in human platelets by suppressing calcium mobilization. J Nutr 2006;136:789S-792S.View Abstract
  • 73.Kiesewetter H, Jung F, Mrowietz C et al. Effects of garlic on blood fluidity and fibrinolytic activity: a randomised, placebo-controlled, double-blind study. Br J Clin Pract Suppl 1990;69:24-29.View Abstract
  • 74.Bordia A, Verma SK, Srivastava KC. Effect of garlic (Allium sativum) on blood lipids, blood sugar, fibrinogen and fibrinolytic activity in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty Acids 1998;58:257-263.View Abstract
  • 75.Gadkari JV, Joshi VD. Effect of ingestion of raw garlic on serum cholesterol level, clotting time and fibrinolytic activity in normal subjects. J Postgrad Med 1991;37:128-131.View Abstract
  • 76.Apitz-Castro R, Escalante J, Vargas R, Jain MK. Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, forskolin, indomethacin and dypiridamole on human platelets. Thromb Res 1986;42:303-311.View Abstract
  • 77.Harenberg J, Giese C, Zimmermann R. Effect of dried garlic on blood coagulation, fibrinolysis, platelet aggregation and serum cholesterol levels in patients with hyperlipoproteinemia. Atherosclerosis 1988;74:247-249.View Abstract
  • 78.Teweleit S, Kuschel U, Hippius M et al. [Manifestation and prevention of adverse drug reactions (ADR) in the pharmacotherapy of cardiovascular diseases]. Med Klin 2001;96:442-450.View Abstract
  • 79.Pirmohamed M, James S, Meakin S et al. Adverse drug reactions as cause of admission to hospital: prospective analysis of 18,820 patients. BMJ 2004;329:15-19.View Abstract
  • 80.Brouwer CA, Gietema JA, van den Berg MP et al. Long-term cardiac follow-up in survivors of a malignant bone tumour. Ann Oncol 2006;17:1586-1591.View Abstract
  • 81.Ewer M, Benjamin R. Cardiotoxcity of chemotherapeutic drugs. In: Perry M, ed. The Chemotherapy Source Book. 3rd ed. Philadelphia: Lippincott, Williams & Wilkins; 2001:458-468.
  • 82.Kojima R, Toyama Y, Ohnishi ST. Protective effects of an aged garlic extract on doxorubicin-induced cardiotoxicity in the mouse. Nutr Cancer 1994;22:163-173.View Abstract
  • 83.Dwivedi C, John LM, Schmidt DS, Engineer FN. Effects of oil-soluble organosulfur compounds from garlic on doxorubicin-induced lipid peroxidation. Anticancer Drugs 1998;9:291-294.View Abstract
  • 84.Thabrew MI, Samarawickrema NA, Chandrasena LG, Jayasekera S. Protection by garlic against Adriamycin-induced alterations in the oxido-reductive status of mouse red blood cells. Phytother Res 2000;14:215-217.View Abstract
  • 85.Mukherjee S, Banerjee SK, Maulik M et al. Protection against acute Adriamycin-induced cardiotoxicity by garlic: role of endogenous antioxidants and inhibition of TNF-α expression. BMC Pharmacol 2003;3:16.View Abstract
  • 86.Borek C. Antioxidant health effects of aged garlic extract. J Nutr 2001;131:1010S-1015S.View Abstract
  • 87.Arora A, Seth K, Shukla Y. Reversal of P-glycoprotein-mediated multidrug resistance by diallyl sulfide in K562 leukemic cells and in mouse liver. Carcinogenesis 2004;25:941-949.View Abstract
  • 88.Chen C, Kong A-NT. Dietary chemopreventive compounds and ARE/EpRE signaling. Free Radical Biol Med 2004;36:1505-1516.
  • 89.Gebhardt R. Multiple inhibitory effects of garlic extracts on cholesterol biosynthesis in hepatocytes. Lipids 1993;28:613-619.View Abstract
  • 90.Qureshi AA, Abuirmeileh N, Din ZZ et al. Inhibition of cholesterol and fatty acid biosynthesis in liver enzymes and chicken hepatocytes by polar fractions of garlic. Lipids 1983;18:343-348.View Abstract
  • 91.Gebhardt R. Inhibition of cholesterol biosynthesis by a water-soluble garlic extract in primary cultures of rat hepatocytes. Arzneimittelforschung 1991;41:800-804.View Abstract
  • 92.Liu L, Yeh YY. S-alk(en)yl cysteines of garlic inhibit cholesterol synthesis by deactivating HMG-CoA reductase in cultured rat hepatocytes. J Nutr 2002;132:1129-1134.View Abstract
  • 93.Kumar RV, Banerji A, Kurup CK, Ramasarma T. The nature of inhibition of 3-hydroxy-3-methylglutaryl CoA reductase by garlic-derived diallyl disulfide. Biochim Biophys Acta 1991;1078:219-225.View Abstract
  • 94.Singh DK, Porter TD. Inhibition of sterol 4α-methyl oxidase is the principal mechanism by which garlic decreases cholesterol synthesis. J Nutr 2006;136:759S-764S.View Abstract
  • 95.Silagy CA, Neil HA. A meta-analysis of the effect of garlic on blood pressure. J Hypertens 1994;12:463-468.View Abstract
  • 96.Langsjoen PH, Langsjoen AM. The clinical use of HMG CoA-reductase inhibitors and the associated depletion of coenzyme Q10: a review of animal and human publications. Biofactors 2003;18:101-111.View Abstract
  • 97.Lang A, Lahav M, Sakhnini E et al. Allicin inhibits spontaneous and TNF-α induced secretion of proinflammatory cytokines and chemokines from intestinal epithelial cells. Clin Nutr 2004;23:1199-1208.View Abstract
  • 98.Horie T, Matsumoto H, Kasagi M et al. Protective effect of aged garlic extract on the small intestinal damage of rats induced by methotrexate administration. Planta Med 1999;65:545-548.View Abstract
  • 99.Horie T, Awazu S, Itakura Y, Fuwa T. Alleviation by garlic of antitumor drug-induced damage to the intestine. J Nutr 2001;131:1071S-1074S.View Abstract
  • 100.Khosla P, Karan RS, Bhargava VK. Effect of garlic oil on ethanol induced gastric ulcers in rats. Phytother Res 2004;18:87-91.View Abstract
  • 101.Piscitelli SC, Burstein AH, Welden N et al. The effect of garlic supplements on the pharmacokinetics of saquinavir. Clin Infect Dis 2002;34:234-238.View Abstract
  • 102.Gallicano K, Foster B, Choudhri S. Effect of short-term administration of garlic supplements on single-dose ritonavir pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2003;55:199-202.View Abstract
  • 103.Patel J, Buddha B, Dey S et al. In vitro interaction of the HIV protease inhibitor ritonavir with herbal constituents: changes in P-gp and CYP3A4 activity. Am J Ther 2004;11:262-277.View Abstract
  • 104.Mouly SJ, Paine MF, Watkins PB. Contributions of CYP3A4, P-glycoprotein, and serum protein binding to the intestinal first-pass extraction of saquinavir. J Pharmacol Exp Ther 2004;308:941-948.View Abstract
  • 105.Gisolf EH, van Heeswijk RP, Hoetelmans RW, Danner SA. Decreased exposure to saquinavir in HIV-1-infected patients after long-term antiretroviral therapy including ritonavir and saquinavir. AIDS 2000;14:801-805.View Abstract
  • 106.Sunter WH. Warfarin and garlic [letter]. Pharmacol J 1991;246:722.
  • 107.Fugh-Berman A, Ernst E. Herb-drug interactions: review and assessment of report reliability. Br J Clin Pharmacol 2001;52:587-595.View Abstract
  • 108.Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998;158:2200-2211.View Abstract
  • 109.Rozenfeld V, Sisca T, Callahan A, Crain J. Double-blind, randomized, placebo-controlled trial of aged garlic extract inpatients stabilized on warfarin therapy [poster]. American Society of Clinical Pharmacists, Mid-year Clinical Meeting. Las Vegas; 2000.
  • 110.Pathak A, Leger P, Bagheri H et al. Garlic interaction with fluindione: a case report. Therapie 2003;58:380-381.View Abstract
  • 111.Comets E, Pousset F, Mentre F et al. Prediction of fluindione maintenance dosage hampered by large intraindividual variability. Ther Drug Monit 2000;22:668-675.View Abstract
  • 112.Loebstein R, Yonath H, Peleg D et al. Interindividual variability in sensitivity to warfarin—nature or nurture? Clin Pharmacol Ther 2001;70:159-164.
  • 113.Fitzmaurice DA, Blann AD, Lip GY. Bleeding risks of antithrombotic therapy. BMJ 2002;325:828-831.View Abstract
  • 114.Wells PS, Holbrook AM, Crowther NR, Hirsh J. Interactions of warfarin with drugs and food. Ann Intern Med 1994;121:676-683.View Abstract
  • 115.Borgert CJ, Borgert SA, Findley KC. Synergism, antagonism, or additivity of dietary supplements: application of theory to case studies. Thromb Res 2005;117:123-132; discussion 145-151.View Abstract
  • 116.Marder VJ. The interaction of dietary supplements with antithrombotic agents: scope of the problem. Thromb Res 2005;117:7-13; discussion 39-42.View Abstract
  • 117.Ciplea AG, Richter KD. The protective effect of Allium sativum and crataegus on isoprenaline-induced tissue necroses in rats. Arzneimittelforschung 1988;38:1583-1592.View Abstract
  • 118.Saxena KK, Gupta B, Kulshrestha VK et al. Effect of garlic pretreatment on isoprenaline-induced myocardial necrosis in albino rats. Indian J Physiol Pharmacol 1980;24:233-236.View Abstract
  • 119.Banerjee SK, Sood S, Dinda AK et al. Chronic oral administration of raw garlic protects against isoproterenol-induced myocardial necrosis in rat. Comp Biochem Physiol C Toxicol Pharmacol 2003;136:377-386.View Abstract
  • 120.Brinker F. Herb Contraindications and Drug Interactions. 3rd ed. Sandy, Ore: Eclectic Medical Publications; 2001.
  • 121.Martin N, Bardisa L, Pantoja C et al. Experimental cardiovascular depressant effects of garlic (Allium sativum) dialysate. J Ethnopharmacol 1992;37:145-149.View Abstract
  • 122.Martin N, Bardisa L, Pantoja C et al. Anti-arrhythmic profile of a garlic dialysate assayed in dogs and isolated atrial preparations. J Ethnopharmacol 1994;43:1-8.View Abstract
  • 123.Martin N, Bardisa L, Pantoja C et al. Involvement of calcium in the cardiac depressant actions of a garlic dialysate. J Ethnopharmacol 1997;55:113-118.View Abstract
  • 124.Jain RC, Vyas CR. Garlic in alloxan-induced diabetic rabbits. Am J Clin Nutr 1975;28:684-685.View Abstract
  • 125.Mathew PT, Augusti KT. Studies on the effect of allicin (diallyl disulphide-oxide) on alloxan diabetes. I. Hypoglycaemic action and enhancement of serum insulin effect and glycogen synthesis. Indian J Biochem Biophys 1973;10:209-212.View Abstract
  • 126.Zhang XH, Lowe D, Giles P et al. Gender may affect the action of garlic oil on plasma cholesterol and glucose levels of normal subjects. J Nutr 2001;131:1471-1478.View Abstract
  • 127.Huang CN, Horng JS, Yin MC. Antioxidative and antiglycative effects of six organosulfur compounds in low-density lipoprotein and plasma. J Agric Food Chem 2004;52:3674-3678.View Abstract
  • 128.Ahmad MS, Ahmed N. Antiglycation properties of aged garlic extract: possible role in prevention of diabetic complications. J Nutr 2006;136:796S-799S.View Abstract