Side Effects, Allergic Reactions & Reporting
What to do if a natural remedy or supplement seems to cause a side effect or allergic reaction, when to call for emergency help, and where problems can be reported.
Content last updated . This page has not been medically reviewed.
Emergency signs come first
Call 911 if a person collapses, has a seizure, has trouble breathing or cannot be woken. [1] A severe allergic reaction (anaphylaxis) can include difficulty breathing, hives, or swelling of the face, eyes or tongue. MedlinePlus calls it an emergency that needs medical attention right away and says to call 911 or the local emergency number. [2]
If someone may have swallowed too much of something, call Poison Help at 1-800-222-1222 (US) and do not make the person vomit. [1] See Poisoning: what to do first.
If you notice a side effect that is not an emergency
NCCIH, part of the US National Institutes of Health, advises: if you have side effects from a dietary supplement, stop taking the supplement and contact your health care provider. It adds that you may also want to contact the supplement manufacturer. [3] That advice is about supplements. If you also take prescribed medicines, do not change those on your own: ask the prescriber or pharmacist what to do.
For a step-by-step list, see What to do after a reaction.
Possible liver warning signs
MedlinePlus lists changes in the color of stool and urine, and jaundice (yellowing of the skin and eyes), among the symptoms of liver disease. It also says that sometimes there are no symptoms. [4] NCCIH notes that more cases of sudden liver damage are being reported in people taking dietary supplements in the United States and elsewhere. [3] If you notice these signs after starting a remedy, contact a clinician promptly. More on this in Liver safety.
Why reporting matters
Reporting is separate from getting care. FDA says its reporting systems are for reporting problems and neither provides medical advice, so contact your health care professional first and then report. [5] FDA tracks side effects reported by consumers, supplement companies and others. [3]
| Where | What the sources we read say | Details |
|---|---|---|
| United States | FDA says adverse events linked to dietary supplements should be reported through the online Safety Reporting Portal. [5] The FDA MedWatch page we read lists dietary supplements among the products it covers, so the two routes are described differently on different FDA pages. [6] | More about United States → |
| United Kingdom | The Yellow Card scheme, run by the MHRA, accepts reports about medicines, vaccines and medical devices. [7] | More about United Kingdom → |
| Canada | Health Canada says anyone can report a side effect to a health or cannabis product. [8] | Same page as above |
| European Union | EMA cannot accept side effect reports directly from patients. [9] Reports go to the national authority. | Same page as above |
Pets and animals
FDA lists a separate route for animal and veterinary products. [6] Animal poison lines are also separate from human poison centers. See Pet and animal poisoning.
What these sources do not cover
Our sources describe where to report, not how likely a remedy is to cause a given reaction. Whether a remedy interacts with a medicine is covered in How interactions work. We did not read an Australian reporting page this session, so Australia is not described here.
Frequently asked questions
Should I stop a supplement if I get side effects?
NCCIH advises stopping the supplement and contacting your health care provider. [3] If you take prescribed medicines, ask the prescriber or pharmacist before changing them.
Do I have to see a doctor before I can report a problem?
No. FDA says your health care provider is not required to report and that you may complete the online form yourself, though it encourages taking the form to your doctor. [6]
Does reporting give me medical advice?
No. FDA says its complaint system and MedWatch are for reporting problems and neither provides medical advice. [5] Yellow Card also says it cannot give medical advice. [7]
Is an allergic reaction to a natural remedy an emergency?
Difficulty breathing or swelling of the face, eyes or tongue can signal anaphylaxis, which MedlinePlus says needs medical attention right away. [2] Call 911 or your local emergency number.
Can I report a problem outside the United States?
Yes, through your country's own system. Canada and the UK are described on our reporting page for other countries. [8][7]
References
- Poison Control (America's Poison Centers). First aid: Act fast!. Read 2026-10-23.
- MedlinePlus (National Library of Medicine). Anaphylaxis. Read 2026-10-23.
- NCCIH (National Institutes of Health, United States). Using Dietary Supplements Wisely. Read 2026-10-23.
- MedlinePlus (National Library of Medicine). Liver diseases. Read 2026-10-23.
- U.S. Food and Drug Administration. FDA 101: How to Use the Consumer Complaint System and MedWatch. Consumer update. Read 2026-10-23.
- U.S. Food and Drug Administration. Reporting Serious Problems to FDA. Page content current as of 09/26/2025. Read 2026-10-23.
- Medicines and Healthcare products Regulatory Agency (United Kingdom). Yellow Card reporting site. Read 2026-10-23.
- Health Canada. Adverse reaction reporting (MedEffect Canada). Text read through a page-fetch tool, 2026-10-23.
- European Medicines Agency. Frequently asked questions: reporting suspected side effects. Read 2026-10-23.