Diarrhoea after a fever

Fever can occur with infections that affect the gut, and loose stools may appear as the illness develops or while the body settles afterwards. Medicines taken during the illness can also irritate the bowel. Respiratory illnesses such as COVID-19 may sometimes include digestive symptoms, while other fever causes have different patterns.

The fever itself does not establish the cause of diarrhoea. Note whether there is abdominal pain, vomiting, blood or mucus, a rash, breathing difficulty, or recent travel, food exposure, or antibiotic use.

Sip water regularly and use an oral rehydration solution according to its instructions if stools are frequent or you are also vomiting. Eat small portions when able, choosing familiar foods, and wash hands carefully after using the toilet. Avoid preparing food for others while unwell.

Rest and monitor urine, alertness, fever, and the frequency of stools. Do not use leftover antibiotics. Ask a clinician or pharmacist before taking an anti-diarrhoeal medicine, particularly for a child, older adult, or person with a long-term condition.

Seek urgent care for severe dehydration, confusion, fainting, severe abdominal pain, blood or black stool, repeated vomiting, breathing difficulty, or a fever that returns with worsening illness. Arrange medical advice when diarrhoea is not settling, you cannot keep fluids down, or the person is very young, older, pregnant, or medically vulnerable.

Ask whether you need testing, how to replace fluids, whether a recent medicine could be responsible, and which symptoms should prompt same-day review. Tell them when the fever began and what treatments you have taken.