There are many different causes of diarrhoea, but a bowel infection (Gastroenteritis) is a common cause in both adults and children. Gastroenteritis can be caused by: a virus – such as norovirus or rotavirus bacteria – such as campylobacter and Escherichia coli (E. coli), which are often picked up from contaminated food a parasite – such as the parasite that causes giardiasis, which is spread in contaminated water Most cases of diarrhoea clear up after a few days without treatment, However, diarrhoea can lead to dehydration, so you should drink plenty of fluids  ORS solution. Antibiotics for infective causes...