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Botanical Name: Ganoderma lucidum (W. Curtis.: Fr.) P. Karst.
Pharmacopoeial Name: Fructus ganodermi.
Synonym: Boletus lucidus Fr.
Common Names: Reishi, reishi mushroom, red reishi; Ling Zhi. ( Ganoderma japonicum = black reishi; Ganoderma applanatum = artist’s conk).

Summary Table
Drug/Class Interaction TypeMechanism and SignificanceManagement
Acyclovir, cefazolin

Synergistic effects (greater than additive) have been observed with antimicrobial and antiviral combinations. Significance not established generally.Consider coadministration, especially for immunocompromised patients with chronic viral and microbial infection.
Immunosuppressive, myelosuppressive chemotherapy
Multifactorial interaction between reishi and chemotherapy; combination may improve therapeutic outcomes. Clinical significance anecdotally established.
Related mushroom polysaccharides also effective.
Consider pretreatment, coadministration, and posttreatment with chemotherapy.
herb description


Ganodermataceae (Polyporaceae).

Related Species

Ganoderma japonicum (Fr.) Lloyd. (synonym, G. sinense Zhao, Xu et Zhang.), Ganoderma applanatum (Pers.) Pat, Ganoderma tsugae Murrill.

Habitat and Cultivation

A woody shelf-fungus that grows on rotting tree stumps and fallen logs in temperate forests throughout much of North America, most of Europe, South America and Asia, typically affecting oak trees. Reishi is now rare in the wild in China and rarer in Japan but has been under widespread industrial-scale cultivation in China for several years, which constitutes the bulk of commercial reishi supply internationally.

Parts Used

Fruiting body. Spore and mycelium preparations exist but have limited commercial availability; they are not identical to the fruiting body in composition or activity.

Common Forms

Dried whole fruiting body, by decoction (or very finely powdered).

  • Tincture:   Traditionally, rice wine extract.

  • Standardized Solid Extract:   Concentrates available greater than 20:1.

interactions review

Strategic Considerations

Traditional Chinese use of reishi includes stand-alone herb for various conditions (Chinese syndrome-patterns), including heart (Xin) qi and lung (Fei) qi deficiencies. 1 In modern Western usage, reishi is primarily considered as a safe and virtually nontoxic immunomodulatory agent. It is primarily used in the clinical context of immunocompromise, such as chronic fatigue immune dysfunction syndrome (CFIDS), or as an adjunct in integrative cancer protocols to support patients undergoing myelosuppressive conventional therapies. Pharmacological data suggest four primary areas of activity for reishi extracts: immune enhancing and antitumorigenic, cardiovascular regulatory, hypoglycemic, and hepatoprotective. 2 Of these, interactions with pharmaceuticals are suggested primarily by the immunomodulatory data.

Support for use of reishi in oncological settings is largely derived from experimental studies on the biological activities of its polysaccharide and triterpene compounds. These have direct antitumor activity mediated by several pathways, notably the inhibition of the key transcription factors nuclear factor-kappa B (NF-κB) and activating protein 1 (AP-1). The indirect anticancer effects are mediated by promotion of mixed-lymphocyte responses, including enhancement of cytotoxic activity of monocyte-macrophages, natural killer (NK) cells, and lymphokine-activated killer (LAK) cells and increased secretion of cytokines such as interleukin-1 (IL-1), IL-6, and interferon gamma (IFN-γ). 3-5Protection against myelosuppression from chemotherapeutic agents and radiation therapy has moderate experimental and anecdotal clinical support; however, clinical trials are required to establish the efficacy of reishi for this purpose. Although some sources have cited Chinese-language clinical studies in support of these uses, full translations are unavailable, and evaluation of these trials by these secondary sources is typically schematic. 6

More substantial clinical data are available for related mushrooms, such as Coriolus, Polyporus, and Lentinus, and medicinal mushroom polysaccharides, particularly the branched (1→3)-beta-Dglucans, are thought to be broadly similar in their general immunomodulatory and anticancer effects. 7,8Additive interactions with antimicrobial pharmaceutical agents have been reported (see later), but these probably are also indirect results from a general enhancement of cell-mediated immunity and antiviral activity by reishi compounds, rather than specific herb-drug interactions. The long-term use of immunomodulating herbs in patient populations dependent on immunosuppressive therapies (e.g., to prevent graft rejection) is de facto contraindicated, and reishi extracts have been shown to reverse immunosuppressive effects of morphine. 9

Cardiovascular drug interactions seem unlikely given the mild cardiotonic effects of reishi despite suggestions in secondary literature of possible potentiating interactions with cholesterol-lowering and anticoagulant drugs. These interactions have not been demonstrated or reported, and claims of their likelihood are classified as “speculative” here, along with equally hypothetical suggestion of interactions with hypoglycemic drugs, as discussed later.

Effects on Drug Metabolism and Bioavailability

Pharmacokinetic interactions between reishi and pharmaceutical drugs have not been reported, and studies on the effects of the herb on drug-metabolizing systems have not been conducted to date. Induction of human hepatic glutathione- S-transferase in vitro by reishi polysaccharide has been recorded in one in vitro study. 10 Inhibition of beta-glucuronidase in vitro by the triterpene constituent ganoderenic acid A was demonstrated in vitro, and the same constituent had a potent inhibitory effect against carbon tetrachloride (CCl4)–induced hepatotoxicity in a rodent model. 11

The hepatoprotective effects of the herb may counter solvent and other chemical or solvent-induced hepatotoxicity. 12,13These effects on drug-metabolizing enzymes may contribute, along with the antioxidant effects of the herb, to the established hepatoprotective properties of reishi observed in some studies. From these limited data, the potential theoretically exists for some modulation of clearance of glucuronide prodrugs, as well as accelerated clearance of glutathione and glucuronated drug conjugates. The effects of variation in activity of beta-glucuronidase on drug metabolism have not been systematically studied to date, but it may be a clinically significant determinant of variability of individual response to pharmaceuticals. 14

herb-drug interactions
Antimicrobial and Antiviral Therapies
Antineoplastic Therapies, Including Anthracyclines, Radiotherapy, and Surgery
theoretical, speculative, and preliminary interactions research, including overstated interactions claims
Anticoagulants, Oral Vitamin K Antagonists
Central Stimulants; Chlorpromazine, Phenobarbital, Reserpine
HMG-CoA Reductase Inhibitors (Statins) and Other Cholesterol-Lowering Drugs
Insulin and Oral Hypoglycemic Agents
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