When to worry about diarrhoea with gastroenteritis

Gastroenteritis irritates the stomach and bowel, often causing loose or watery stools, cramps, nausea, vomiting and sometimes fever. Fluid and salts leave the body in diarrhoea, so thirst, a dry mouth, dark urine, dizziness or passing urine less often can signal dehydration. These warning signs matter more than the number of bowel movements alone.

Take frequent small sips of water or an oral rehydration solution. Continue light meals when you can, choosing foods you tolerate, and rest. Avoid preparing food for other people while ill and wash your hands carefully after using the toilet. Do not take anti-diarrhoea medicine if you have blood in the stool or a high fever without asking a clinician.

Get urgent medical help if you cannot keep fluids down, feel faint or confused, have severe or persistent abdominal pain, blood or black stool, or signs of marked dehydration. Arrange medical advice if symptoms are worsening, do not start settling, or affect a young child, older adult, pregnant person, or someone with a significant medical condition.

Ask whether you need testing, how to replace fluids and salts, and which medicines are suitable for you. Tell the clinician when the diarrhoea began, whether vomiting or fever is present, what the stool looks like, and how often you are passing urine.