Why does norovirus infection cause diarrhoea?

During norovirus infection, the digestive tract may move contents along quickly and absorb fluid less effectively. More water remains in the stool, making bowel motions loose and frequent. Cramping, nausea, vomiting, and tiredness can occur alongside diarrhoea.

Diarrhoea is a very common presentation of Norovirus Infection. Loose stools also have many other causes, including other infections, food-related illness, medicines, and bowel conditions, so the symptom alone cannot confirm norovirus.

The immediate priority is replacing fluid. Take frequent small sips of water or an oral rehydration drink, especially after loose stools. Rest when you can and return to food as appetite allows; simple foods may be easier to tolerate at first.

Wash hands carefully with soap and water after using the toilet and before preparing food. Avoid preparing food for others while unwell, and clean frequently touched bathroom surfaces to reduce spread.

Get medical advice if you cannot keep fluids down, have signs of dehydration such as very little urine, dizziness, or unusual drowsiness, or if diarrhoea is persistent or worsening. Seek urgent care for blood in stool, severe abdominal pain, confusion, fainting, or severe weakness.

Ask whether your symptoms suggest dehydration, which drinks are suitable for you, whether any regular medicines need special attention while you are unwell, and which warning signs should prompt urgent review.