When is a stomach bug contagious?

Gastroenteritis can spread when microscopic particles from stool or vomit reach another person’s mouth. Hands, bathroom fixtures, shared towels, food and frequently touched surfaces can carry these particles. A person may spread infection while symptoms are active, and some viruses can remain transmissible after the person feels better. The exact contagious period varies with the cause, so symptom improvement does not replace hygiene.

Wash hands with soap and water after using the toilet, changing nappies or cleaning vomit, and before eating or preparing food. Clean bathroom and kitchen touchpoints with an appropriate disinfectant. Do not share towels, cups or utensils, and wash soiled laundry separately when possible. Stay home while actively vomiting or having diarrhoea and follow local workplace or school advice before returning.

Seek medical care for dehydration, repeated vomiting, blood in stool or vomit, severe abdominal pain, confusion, fainting or a concerning fever. Ask for earlier advice if the unwell person is a young child, older adult, pregnant or immunocompromised. Contact a clinician if several people become ill after the same meal or in the same setting, because additional public-health guidance may be needed.

Ask when you can safely return to work or school, how to clean the home, and whether a vulnerable household member needs specific precautions.