Why does gastroenteritis cause diarrhoea?

Diarrhoea is a very common presentation of Gastroenteritis. Infection or irritation can also prompt the bowel to release more fluid, adding to loose or watery stools.

Loose stools can occur with cramps, urgency, nausea, vomiting, reduced appetite, or fever. The main immediate concern is fluid loss, particularly when diarrhoea and vomiting happen together.

Gastroenteritis is one possible cause of diarrhoea, but food intolerance, medicines, bowel conditions, and other infections can produce similar symptoms. The course and associated symptoms help guide assessment.

Replace fluids steadily with small, frequent drinks. Oral rehydration solutions can be useful when fluid losses are substantial; a pharmacist can help you choose an appropriate product.

Eat simple foods when you feel able, and avoid alcohol until you are recovering. Wash hands with soap and water after using the toilet and before handling food to lower the chance of passing infection to others.

Seek urgent care for blood in stool, black tar-like stool, severe or worsening abdominal pain, fainting, confusion, repeated vomiting that stops you drinking, or dehydration signs such as marked dizziness or very little urine.

Contact a clinician if diarrhoea continues, you have persistent fever, symptoms disrupt normal activity, or you have a weakened immune system, inflammatory bowel disease, or another significant health condition.

Ask whether you need a stool test, how to recognise dehydration, and whether your current medicines need adjustment while you are unwell. Record the onset of symptoms, stool appearance, recent travel, sick contacts, and any food or medicine changes.