When to Seek Medical Help
A plain guide to which problems after a mushroom supplement, coffee or meal need 911, Poison Help or a clinician, from allergic reactions to liver and kidney warning signs.
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.
For an emergency, call 911 (US). That includes collapse, a seizure, trouble breathing, or a person who cannot be woken. [1] Anaphylaxis, a severe whole-body allergic reaction, is an emergency that needs medical attention right away. [2] For a possible poisoning, call Poison Help at 1-800-222-1222, which is free and open 24 hours a day. [1]
This page is information only. It cannot tell you whether a symptom is serious; a clinician can.
Quick guide
| What happened | What to do | Source |
|---|---|---|
| Swelling of the face, eyes or tongue, difficulty breathing, or symptoms that start within seconds or minutes of exposure | Call 911 or your local emergency number | [2] |
| Collapse, seizure, trouble breathing or cannot be woken | Call 911 immediately | [1] |
| Ate a wild or unknown mushroom | Call Poison Help now; do not wait for symptoms | [3] |
| Took too much of a product, or a child swallowed one | Call Poison Help | [1] |
| Yellow skin or eyes, or belly pain, after reishi or another mushroom supplement | Contact a clinician promptly; call 911 if severe | [4] [5] |
| Changes in kidney tests after chaga | Tell your kidney team; stop the product | [6] |
| Unusual bleeding after dental work or surgery while using cordyceps | Tell your dentist or surgeon | [7] |
| Illness after a mushroom meal, such as enoki | Contact a health care provider | [8] |
| Hives, itching or stomach upset after a mushroom food or product | See a clinician; see the allergy notes below | [9] |
| Fast heartbeat, jitters or headache after mushroom coffee | Talk with a health care professional | [10] |
Allergic reactions
Anaphylaxis symptoms develop quickly, often within seconds or minutes, and can include swelling of the face, eyes or tongue and difficulty breathing. [2] A 2022 review says edible mushrooms can trigger fungus food allergy, with symptoms ranging from oral allergy syndrome to severe anaphylaxis. [11] The NHS (UK) notes that food allergy symptoms can start straight after eating, or days later, and may include itchy skin or a raised rash (hives). [9]
MSK lists skin inflammation and increased sensitivity to sunlight among shiitake side effects, and pneumonia caused by hypersensitivity to spores. [12] See mushroom allergy and food intolerance and side effects and allergies by type.
Bleeding
MSK describes a case report of excessive bleeding after a tooth extraction in someone using cordyceps daily as a tonic. [7] See surgery and bleeding.
Mushroom coffee and caffeine
The FDA has cited 400 milligrams of caffeine a day as an amount not generally associated with negative effects for most adults. [10] Too much caffeine can cause increased heart rate, palpitations, high blood pressure, sleep disruption, anxiety, jitters, upset stomach, nausea and headache. [10] The FDA advises talking with a health care professional if you have these symptoms. [10] See mushroom coffee side effects.
Food illness
After an outbreak linked to enoki mushrooms, the FDA said anyone with symptoms should contact a health care provider. [8] CDC and FDA advise people who are pregnant, 65 or older or with a weakened immune system to cook enoki thoroughly. [8]
Self-harm or intentional overdose
America's Poison Centers says that when the intent is self-harm, evaluation by a health care provider, usually in an ER, is always advised. [1] In the US you can call 988 (Suicide & Crisis Lifeline) or 911.
Not urgent, but worth reporting
For mild stomach upset, trouble sleeping or other new symptoms, ask your pharmacist or clinician, and see side effects, allergic reactions and reporting. Bring the product label. For a wild mushroom, see mushroom poisoning: warning signs and urgent help.
Frequently asked questions
What number do I call for a mushroom poisoning?
In the US, Poison Help is 1-800-222-1222; call 911 for collapse, a seizure, trouble breathing or if the person cannot be woken. [1]
How fast can an allergic reaction start?
Anaphylaxis symptoms often develop within seconds or minutes. [2]
Can I wait to see if I feel better after a wild mushroom?
No. Call Poison Help without waiting for symptoms. [3]
What are signs of liver trouble?
Yellow skin or eyes are one sign; other causes exist, so see a clinician. [4]
Who do I tell about my supplement?
Your pharmacist, prescriber, surgeon and dentist; bring the label.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Liver and kidney warning signs
Jaundice causes the skin and the whites of the eyes to turn yellow. [4] MSK lists liver injury among reishi side effects. [5] A reported case began with headache and abdominal pain after reishi powder and alcohol. [13] For chaga, case reports describe kidney damage from oxalate. [6] Details: kidneys, oxalates and the liver and liver safety.
References
- Poison Control (America’s Poison Centers). Need immediate assistance?. Read 2026-10-23.
- MedlinePlus (U.S. National Library of Medicine). Anaphylaxis. Read 2026-10-23.
- The University of Kansas Health System Poison Control Center. Poisonous Mushrooms. Read 2026-10-23.
- MedlinePlus (U.S. National Library of Medicine). Jaundice. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Reishi Mushroom (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Kikuchi Y, et al. Chaga mushroom-induced oxalate nephropathy. Clin Nephrol. 2014. PubMed 23149251. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Cordyceps (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- U.S. Food and Drug Administration. Outbreak Investigation of Listeria monocytogenes: Enoki Mushrooms (November 2022). Read 2026-10-23.
- NHS (UK). Food allergy. Read 2026-10-23.
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much?. Read 2026-10-23.
- Xing H, et al. Recent Advances in the Allergic Cross-Reactivity between Fungi and Foods. J Immunol Res. 2022. PubMed 36249419. Read 2026-10-23.
- Memorial Sloan Kettering Cancer Center. Shiitake Mushroom (About Herbs, Botanicals and Other Products). Read 2026-10-23.
- Guedikian R, et al. Ganoderma lingzhi (Reishi Mushroom)-Induced Acute Liver Injury in the Setting of Alcohol Use: A Case Report and Review of the Literature. Cureus. 2023. PubMed 37885515. Read 2026-10-23.