Microscopic colitis is a subset of inflammatory bowel disease.

Patients typically have profuse watery diarrhoea, often with urgency, incontinence, and nocturnal symptoms.

Primary care investigations are usually normal.

The bowel mucosa usually appears normal, and biopsies are needed for a histological diagnosis.

Treatment is with oral budesonide 9 mg/day for an initial period of 6–8 weeks.