Mushroom Supplements Before Surgery and With Bleeding Risk
What sources say about reishi, cordyceps, chaga and maitake products, bleeding, blood pressure and surgery, and why your surgical team needs to know about every product.
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.
Tell your surgical team about every mushroom product you use. The U.S. National Center for Complementary and Integrative Health (NCCIH) says some dietary supplements may increase the risk of bleeding, may affect the response to anesthetics, and may cause serious changes in heart rate or blood pressure. [1] This page covers what is and is not documented for mushroom products. It is information only. Your surgeon, anesthesia provider and pharmacist decide what is right for you.
What the sources say about bleeding
Evidence differs a lot by mushroom. Most of it is laboratory work or single case reports, so it cannot tell us how often a problem happens.
| Mushroom (product) | What the source found | Label |
|---|---|---|
| Reishi (Ganoderma lucidum) | Memorial Sloan Kettering (MSK) says reishi can increase the risk of bleeding. [2] In a laboratory test, a hot-water extract of G. lucidum showed an antiplatelet effect (platelets are the blood cells that help clots form), although it was also toxic to platelets and white blood cells. [3] In a placebo-controlled trial, healthy volunteers took G. lucidum capsules (1.5 g, as the trial reported) for 4 weeks; clotting tests showed no significant differences from placebo. [4] | Mixed: lab signal, reassuring small trial |
| Cordyceps (Ophiocordyceps sinensis) | MSK lists a case report of excessive bleeding after a tooth extraction in someone using cordyceps daily as a tonic. [5] A 2022 review found Cordyceps sinensis "loosely associated" with surgical bleeding. [6] | Case report and limited review |
| Chaga (Inonotus obliquus) | MSK says chaga may increase bleeding risk; an extract inhibited platelet clumping in mice, and clinical relevance is not known. [7] | Preclinical (animals) |
| Maitake (Grifola frondosa) | MSK describes a case report of a raised INR (a blood-clotting test) in a person taking warfarin and maitake. [8] | Case report |
The lab study screened hot-water extracts of eight edible mushrooms and none changed the standard clotting tests, so a platelet effect in a dish is not the same as bleeding in a person. [3] The trial authors concluded that reishi before surgery is unlikely to raise bleeding risk in otherwise healthy patients. [4] That was one small study of healthy people; it does not cover people on blood thinners.
Reishi and blood pressure
Some readers search for "reishi and blood pressure". Here is what we found.
- A 2015 Cochrane review of G. lucidum (five trials, 398 people) found no statistically significant difference from placebo for blood pressure in the three trials it could analyze, all in people with type 2 diabetes. [9]
- A 2025 meta-analysis of 17 randomized trials also found no significant effect on blood pressure, though it reported a small drop in heart rate. It rated the certainty of the evidence as very low. [10]
Proper evidence not found for a proven blood-pressure-lowering effect, or a proven interaction with blood pressure medicines, for reishi. We searched NCCIH, MSK and PubMed (Cochrane and meta-analyses). That is not proof of safety. NCCIH's general warning about heart rate and blood pressure around surgery still applies to any supplement. [1] For medicine questions see mushroom supplement and medicine interactions.
Before surgery or a dental procedure
- NCCIH says to talk with your providers as far in advance as possible and tell them about all supplements. [1]
- Some providers ask patients to stop all herbal supplements several weeks before elective surgery. [1] One 2022 review's authors suggested stopping nonessential supplements 2 weeks before surgery. [6] Your own team sets the timing.
- If surgery is an emergency, NCCIH says it is still important that you or a loved one tell the surgeon and anesthesia provider about every supplement. [1]
- The cordyceps bleeding report followed a dental extraction, so mention products before dental work too. [5]
Blood thinners
Warfarin is on NCCIH's list of medicines with a narrow therapeutic range, where small changes in blood levels can matter. [1] MSK says to talk with your provider if you take blood thinners and use reishi, chaga, maitake or cordyceps. [2] [7] [8] [5] Do not stop or change a prescribed medicine on your own; ask the prescriber or pharmacist. See also supplements before surgery and how interactions work.
Limits
Products differ in species, part and extract, and a result for one does not transfer to another. Read how to read a mushroom supplement label and bring the bottle to your appointment.
Frequently asked questions
Should I stop my mushroom supplement before surgery?
That is a decision for your surgical team. NCCIH notes that some providers ask patients to stop herbal supplements several weeks before elective surgery, so tell them early. [1]
Does reishi thin the blood?
Sources disagree. MSK says reishi can raise bleeding risk, while a small placebo-controlled trial in healthy volunteers found no change in clotting tests. [2] [4]
Does reishi lower blood pressure?
In the Cochrane review and a 2025 meta-analysis, blood pressure did not differ significantly from placebo. [9] [10]
Are food mushrooms a bleeding concern?
Proper evidence not found for ordinary food portions in the sources we read (MSK herb pages, the 2022 bleeding review and the studies above). The bleeding reports we found involve supplements or tonics.
Who should ask before using these products?
Anyone taking warfarin or other blood thinners, anyone with a bleeding condition, and anyone with surgery or dental work planned. [1]
References
- National Center for Complementary and Integrative Health. Some Medication-Supplement Interactions Can Be Serious. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Reishi Mushroom (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Poniedziałek B, et al. 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.
- Kwok Y, et al. 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.
- Memorial Sloan Kettering Cancer Center. Cordyceps (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Hatfield J, Saad S, Housewright C. Dietary supplements and bleeding. Proc (Bayl Univ Med Cent). 2022. PubMed 36304597. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Chaga Mushroom (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Maitake (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Klupp NL, et al. Ganoderma lucidum mushroom for the treatment of cardiovascular risk factors. Cochrane Database Syst Rev. 2015. PubMed 25686270. Read 2026-10-23.
- Jafari A, et al. 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.