Reporting suspected side effects — the UK Yellow Card scheme

What you can report

• Suspected side effects from any UK-licensed medicine.
• Suspected side effects from a vaccine, herbal product, or medical device.
• Suspected counterfeit, fake, or substandard medicines.
• Suspected adverse events from unlicensed products being used as if they were medicines.
• Defective products (broken pens, contaminated containers, mislabelled packaging).

Why reports matter

The MHRA combines individual reports with other UK and international data to detect safety signals, issue Drug Safety Updates, and act against counterfeit supply chains. A single report rarely changes policy on its own, but a pattern of reports can — and a missing report is data nobody can act on.

How to report

1. Online: via the Yellow Card website at yellowcard.mhra.gov.uk.
2. Yellow Card app: “Yellow Card” in the iOS App Store and Google Play.
3. By phone: via the MHRA's published contact route (see Yellow Card site for the current number).

You do not have to be certain a medicine caused the effect. The scheme is for suspected reactions. Healthcare professionals are encouraged to submit reports too — and patients can report themselves.

What to include in a report

• The medicine or product name, brand, and (if known) batch and expiry.
• The suspected reaction — what happened, when, and how it resolved.
• Other medicines you were taking and any relevant medical history.
• Where you obtained the product (pharmacy, online seller, clinic, social media).
• Whether you think the product may be counterfeit.

If you suspect a counterfeit product

The Yellow Card scheme can be used to flag suspected counterfeit medicines, but the MHRA has a separate route for reporting suspected counterfeit medicine suppliers and enforcement issues. The Yellow Card site signposts the current route. See also our fake weight-loss pens page.