Background

Shiitake mushroom (Lentinus edodes) is a type of edible fungus. It's native to Japan and China, and contains a chemical called lentinan.

Shiitake mushrooms are the second most commonly eaten mushrooms in the world. Lentinan and other chemicals in shiitake mushrooms might stimulate the immune system.

People use shiitake mushroom or an extract called AHCC for HIV/AIDS, common cold, flu, and many other conditions, but there is no good scientific evidence to support these uses. There is also no good evidence to support using shiitake mushroom for COVID-19.

Safety Safety definitions

When taken by mouth: Shiitake mushroom is likely safe when cooked and eaten in food amounts. A specific extract called AHCC is possibly safe in doses ranging from 4.5 to 6 grams daily for up to 6 months or doses of 3 grams daily for up to 9 years. Shiitake mushroom is possibly unsafe when used in larger amounts as medicine, or when the uncooked mushroom is eaten. It can cause stomach discomfort, blood abnormalities, and skin swelling. It might also make the skin more sensitive to the sun and can cause allergic skin reactions and breathing problems in some people.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if shiitake mushroom is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to food amounts.

"Auto-immune diseases" such as multiple sclerosis (MS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), or other conditions: Shiitake mushroom might cause the immune system to become more active. This could increase the symptoms of auto-immune diseases. If you have one of these conditions, it's best to avoid using shiitake mushroom.

A blood disorder called hypereosinophilic syndrome: Don't use shiitake mushroom if you have this condition. It might make it worse.

Effectiveness

Dosing & administration

There isn't enough reliable information to know what an appropriate dose of shiitake mushroom might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Medications changed by the liver (Cytochrome P450 2D6 (CYP2D6) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Shiitake mushroom might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications that decrease the immune system (Immunosuppressants)

Interaction Rating=Moderate Be cautious with this combination.

Shiitake mushroom can increase the activity of the immune system. Some medications, such as those used after a transplant, decrease the activity of the immune system. Taking shiitake mushroom along with these medications might decrease the effects of these medications.

Interactions with herbs & supplements

There are no known interactions with herbs and supplements.

Interactions with foods

There are no known interactions with foods.