Stomach effects can be more than a nuisance
The label for semaglutide (Wegovy), checked September 26, 2026, lists feeling sick, vomiting, loose stools, and trouble passing stool among common unwanted effects.
- That label warns of kidney injury from losing fluid through severe vomiting or diarrhea.
- It does not recommend Wegovy for severe gastroparesis, which means the stomach empties much too slowly.
- The label also reports gallbladder problems such as gallstones. Belly pain that is severe or lasts, and may spread to the back, can be a warning of pancreatitis, a serious inflammation inside the belly. Inflammation means a part of the body becomes swollen and sore.
- Get medical help straight away for that pain. Do not wait for your next routine visit.
Some health histories rule the medicine out
The boxed warning is the strongest warning on an FDA medicine label. It reports thyroid tumors in rats and mice. For people, it remains unknown whether semaglutide causes these tumors.
- Under that label, semaglutide cannot be used by anyone who has had medullary thyroid cancer, or whose family has a history of it; this is a rare thyroid cancer.
- The label also rules out use for MEN 2, a rare illness that a child can inherit from a parent. It also rules out use after a serious allergic reaction to semaglutide or its ingredients.
- If the name MEN 2 is new to you, ask the clinician to check your health and family records. You do not have to recognise the illness by yourself.
- For planned surgery, the label asks patients to tell the surgical team about semaglutide. The label does not settle whether stopping it before surgery reduces harm.
- Pregnancy plans also need discussion because the label describes possible harm to a developing baby.
Know when help is urgent
Emergency help is needed for a severe allergic reaction that causes breathing trouble or swelling of the face or tongue, according to MedlinePlus guidance checked September 17, 2026. For these symptoms, call for emergency help on 911 or your local emergency number.
- Ask the clinician to explain the contact plan before leaving the visit.
- Keep that plan somewhere easy to find.