Every day, medicines improve health and save lives. But even medicines that have been carefully tested and assessed before they reach your medicine cabinet can sometimes cause side effects. Recognizing and reporting these side effects is essential to making medicines safer for everyone.
From 2 to 8 November 2026, WHO joins the global #MedSafetyWeek campaign to raise awareness of the importance of recognizing side effects from medicines and encourage patients, caregivers and healthcare professionals to report them.
Why reporting side effects matters
Side effects can take many forms, from a skin rash or upset stomach to changes in sleep, mood or other unexpected symptoms. Some may appear shortly after starting treatment, while others develop after prolonged use, a change in dose or when several medicines are taken together.
Although medicines undergo rigorous evaluation before they reach patients, not all potential side effects can be identified during clinical trials. Continuous monitoring throughout a medicine's life cycle is therefore essential.
Every report matters. When combined with other reports and scientific evidence, it can help identify potential safety concerns, improve understanding of medicine-related risks and inform actions to protect patients.
The campaign aims to:
- raise awareness and highlight the importance of reporting.
- encourage patients, caregivers and healthcare professionals to recognize and promptly report side effects through national reporting systems, even when they are unsure whether a medicine caused them.
This #MedSafetyWeek, help spread the message: Don't ignore side effects. Report them. Together, we can make medicines safer for everyone.
Learn more and get involved
#MedSafetyWeek is a global campaign led by Uppsala Monitoring Centre, WHO Collaborating Centre for International Drug Monitoring.