Irritable bowel syndrome (IBS). Coloured X-ray of the sigmoid colon (far right to centre) and rectum (lower centre) of a patient suffering from IBS, also known as spastic colon or irritable colon syndrome. IBS causes abdominal pain and irregular bowel habits. The rectum, seen at lower centre, is distended due to either constipation or a build up of gases. The condition is thought to be linked to anxiety and stress, which disturb involuntary muscle movement in the colon. There is no cure, but laxatives, antidiarrhoeal and antispasmodic drugs may alleviate the symptoms. Increasing the intake of fibre and water in the diet, and decreasing stress is also recommended.