Side Effects & Allergies

Mushroom supplements and mushroom foods can cause problems for some people, and the problems differ by species and form. This page lists what the sources we read report, and how strong each report is. Most are case reports, which show that something can happen but not how often. Absence of a report is not proof of safety. A pharmacist or clinician can help you decide what is right for you.

Reported effects by mushroom

Names follow GBIF: Ganoderma lucidum, Hericium erinaceus, Inonotus obliquus, Ophiocordyceps sinensis, Lentinula edodes, Agaricus subrufescens and Trametes versicolor are accepted names. [1]

Two things to notice

First, sources can disagree on wording. The Memorial Sloan Kettering chaga page tells patients there are no reports of side effects, yet its professional section lists kidney failure cases. [18] Read the case reports, not only the summary line.

Second, form matters. In the reishi report, the same patients tolerated boiled reishi but developed liver problems after switching to powder. [3] That is two patients, so it cannot prove the form was the cause, but it is a reason to name the form when you talk to a clinician.

Allergy and sensitivity

Reactions to mushrooms can be food allergy, skin reactions or breathing problems from spores. A review of allergic cross-reactivity describes fungus-related foods, including edible mushrooms, causing reactions ranging from oral allergy symptoms to severe anaphylaxis. [19] In a three-year study of 60 workers in one mushroom factory, over 90% became sensitized to the spores and 40% quit because of symptoms. [20] That is an occupational setting, not eating or taking supplements.

Shiitake rash deserves its own note. In a French review of 125 shiitake exposures, 59 people developed dermatitis after raw or undercooked shiitake, and all recovered completely. [11] Treatments such as steroids or antihistamines showed no demonstrated benefit. [11] The proposed cause is lentinan, a heat-labile compound. [11] See Cooking Edible Mushrooms Safely and Mushroom Allergy and Food Intolerance.

What to do if you have a reaction

Seek urgent care for trouble breathing, swelling or collapse; in the US call 911. For a poisoning concern call Poison Help at 1-800-222-1222. [21] For milder effects, contact a clinician and bring the product label. Reports can go to the FDA's Safety Reporting Portal. [22] See Side Effects, Allergic Reactions and Reporting and the species pages: Reishi Side Effects and Liver Reports, Lion's Mane Side Effects, Chaga Side Effects and Kidney Concerns.