Diarrhoea is an increase in the number of stools with a loose or watery consistency and a faecal weight greater than 200 g in 24 hours.

The frequency and severity depends on whether or not the disease is active.
• Mild diarrhoea may produce four or fewer motions daily.
• Severe diarrhoea may produce six or more motions daily with visible blood.

Large volume diarrhoea is seen often more in small intestine or proximal colon disease (i.e. ileo-caecal).

Frequency and urgency associated with tenesmus is more often a feature of left-sided (distal) colonic disease.

Diarrhoea is a major feature of inflammatory bowel disease and is the defence mechanism of the body in response to inflammation and infection. The transit of faeces (waste) is speeded up in an effort to rid the gut of infection. Symptomatic relief of diarrhoea with drugs such as Codeine is not recommended in the acute phase as it stops this mechanism and in doing so, can mask the underlying disease with possible serious consequences e.g. perforation. The aim is to determine the cause and treat the inflammation, thus relieving the diarrhoea.