Chronic inflammation and ulceration of the large intestine, without specific cause such as a bacterium or virus, often occurring in older children and young adults, but sometimes in later life. Ulcerative colitis is probably an autoimmune disease: the body produces defences against its own tissue. Psychological factors may also be involved, but this is doubted nowadays. The most important symptom is diarrhoea containing blood and mucus, passed up to 40 times per day according to the seriousness of the condition. Sometimes only blood and mucus are passed. Other symptoms are a diminished sense of urgency, fever, loss of weight, convulsive abdominal pain and general malaise, all changing with the severity of the disorder, which tends to flare up and then subside for a time. Serious forms can lead to anaemia and protein deficiency. Complications are perforated stomach ulcers or abscesses and fistulas in the intestine, also inflammation of the eyes and joints and a skin condition (erythema nodosum). The risk of intestinal cancer is increased. If the condition is suspected, rectoscopy provides an adequate diagnosis; this examination is necessary to eliminate other intestinal disorders such as enteritis, malignant tumours or other causes of inflammation of the large intestine, such as dysentery. Treatment has various aspects. Food must be easily digestible (low in fibre) and high in protein; however dairy produce is sometimes not acceptable. The sulphonamide drug sulphasalazine is often prescribed, but if this is ineffective and the early stages of the disorder are associated with high fever, bleeding and severe diarrhoea, corticosteroids may be used, which are generally effective. Hormone treatment can be stopped when the intestine recovers. Thus treatment depends on the symptoms; a complete cure is seldom achieved. If there are serious complications such as perforated ulcers, part of the large intestine may have to be removed.