Reishi and Medicines: Blood Thinners, Blood Pressure, Diabetes and Immune Medicines
Which medicine groups sources flag with reishi (blood thinners, immune medicines, chemotherapy) and which are only theoretical or not described.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Ask before combining. Memorial Sloan Kettering Cancer Center (MSK) advises talking to your healthcare provider if you take blood thinners such as warfarin, because reishi can increase the risk of bleeding, and if you take immunosuppressants, because reishi may not be safe for you. [1] Tell all your healthcare providers about every supplement you take. [1] Never stop or change a prescribed medicine on your own; ask the prescriber or pharmacist. For how "documented" and "theoretical" are used here, see how interactions work.
What the sources say, by medicine group
Interaction evidence for reishi is thin. Most statements come from one summary, lab work and small trials.| Medicine group | What the sources say | Documented or theoretical |
|---|---|---|
| Blood thinners (warfarin, anticoagulants) and antiplatelets | MSK lists a bleeding-risk interaction with anticoagulants and antiplatelets and says reishi extracts may prolong INR, PT and APTT tests. [1] A lab study of hot-water extracts found a G. lucidum extract had antiplatelet effects but did not alter prothrombin time or INR. [2] A 2000 review listed "Ganoderma Japonicum" among herbs said to reinforce warfarin action. [3] In a randomized trial in 40 healthy volunteers, coagulation, platelet-function and thrombelastography tests showed no between-group differences. [4] | Mixed. Lab and review-level concern, not confirmed in the one controlled human trial we read. A case of bleeding with reishi and warfarin: Proper evidence not found. |
| Immunosuppressants (for example after a transplant) | MSK says reishi can enhance immune response and may not be safe for people on immunosuppressants. [1] | Flagged by MSK; mechanism is theoretical |
| Chemotherapy | MSK says reishi can increase plasma antioxidant capacity and in theory may interact with chemotherapy that relies on free radicals. [1] | Theoretical |
| Medicines cleared by liver enzymes (CYP2E1, CYP1A2, CYP3A) | MSK reports that in the lab, reishi polysaccharides inhibited these enzymes; clinical relevance is not known. [1] | Theoretical (lab) |
| Blood pressure medicines | In trials, reishi did not change blood pressure: not in a controlled crossover of adults with borderline blood pressure [5], not in a Cochrane review of five trials [6], and not in a 2025 meta-analysis. [7] An interaction with blood pressure medicines is not described in the sources we read. | Not described; no blood pressure effect shown |
| Diabetes medicines | A Cochrane review found no clear change in blood sugar or HbA1c in people with type 2 diabetes. [6] A small crossover trial found lower plasma insulin and insulin resistance with reishi. [5] Interaction with diabetes medicines is not described in the sources we read, so ask a pharmacist. | Not described; findings mixed |
| Sedatives and sleep medicines | A rat study suggested a benzodiazepine-like effect, at least in part. [8] No human interaction was described in the sources we read. | Animal finding only |
Blood pressure: the plain answer
The searches behind this page found no good evidence that reishi lowers blood pressure and no documented interaction with blood pressure medicines. The 2025 meta-analysis of 17 trials found no significant effect on blood pressure. [7] That is not proof of safety with every medicine. People with high or low blood pressure should still tell their prescriber about any supplement.Bleeding and surgery
The 2005 hemostasis trial gave healthy volunteers reishi capsules for 4 weeks and found no impairment of hemostasis; the authors concluded preoperative use is unlikely to raise surgical bleeding risk in otherwise healthy patients. [4] MSK still advises caution with blood thinners. [1] Because the trial involved healthy people and a single product, tell the surgical and anesthesia teams about reishi in advance. See supplements before surgery and mushroom supplements before surgery.Lab tests
Reishi extracts may prolong INR, PT and APTT. [1] Reishi spore powder was found to raise the tumor marker CA72-4, which can show up on test results and interfere with cancer treatment decisions. [1] Tell the clinician ordering any test.Autoimmune conditions
MSK says reishi may trigger or exacerbate autoimmune skin disease, though cause is not established. [1] A 2025 scoping review placed reishi among 15 immune-stimulating herbal supplements with the most robust evidence. [9]What we could not verify
- The NIH LiverTox reishi page could not be read, so no LiverTox statements are used.
- A PubMed search for Ganoderma or reishi with warfarin, anticoagulant, antiplatelet or bleeding, plus case or interaction, returned no reishi-warfarin case report that we read.
- Pregnancy, breastfeeding and reishi-specific allergy interactions are not described in the sources we read.
- No official monograph on reishi interactions was read.
Other pages
See mushroom supplement and medicine interactions, interactions by drug class and reishi side effects and liver reports.Frequently asked questions
Can I take reishi with warfarin?
MSK says to talk to your healthcare provider because reishi can increase bleeding risk. A small trial in healthy volunteers found no hemostasis changes, so evidence is mixed. [1][4]
Does reishi lower blood pressure?
Trials we read found no change in blood pressure. [6][7]
Is reishi safe with blood pressure medicines?
An interaction is not described in the sources we read. Ask a pharmacist, because absence of reports is not proof of safety.
Does reishi affect diabetes medicines?
Not described in the sources we read. Trial findings on blood sugar were mixed. [6][5]
Should I tell my surgeon about reishi?
Yes. Tell the surgical team and prescriber in advance. [1]
References
- Memorial Sloan Kettering Cancer Center. Reishi Mushroom (Information About Herbs, Botanicals and Other Products). Read 2026-10-23.
- The Effect of Mushroom Extracts on Human Platelet and Blood Coagulation: In vitro Screening of Eight Edible Species. Nutrients. 2019. PubMed 31842490. Read 2026-10-23.
- [Oral anticoagulants and medicinal plants. An emerging interaction]. Ann Ital Med Int. 2000. PubMed 10920504. Read 2026-10-23.
- A prospective, randomized, double-blind, placebo-controlled study of the platelet and global hemostatic effects of Ganoderma lucidum (Ling-Zhi) in healthy volunteers. Anesth Analg. 2005. PubMed 16037156. Read 2026-10-23.
- Study of potential cardioprotective effects of Ganoderma lucidum (Lingzhi): results of a controlled human intervention trial. Br J Nutr. 2012. PubMed 21801467. Read 2026-10-23.
- Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev. 2015. PubMed 25686270. Read 2026-10-23.
- The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials. Food Sci Nutr. 2025. PubMed 40510787. Read 2026-10-23.
- Extract of Ganoderma lucidum potentiates pentobarbital-induced sleep via a GABAergic mechanism. Pharmacol Biochem Behav. 2007. PubMed 17383716. Read 2026-10-23.
- Identifying immunostimulatory herbal supplements that may flare autoimmune skin diseases: a systematic scoping review. Lupus Sci Med. 2025. PubMed 41475897. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.