Colitis is an inflammatory disease of the colon whose cause remains unknown, affecting part or all of the large intestine. It takes several forms — ulcerative colitis, mucus colitis, and ischaemic colitis among them — which differ in symptoms and effects, and its intensity tends to wax and wane over time. Dietary sensitivity is highly individual, but the general advice is to avoid foods and drinks that irritate the bowel: tea, coffee, alcohol, vinegar, spicy foods, fried foods, sugars, and salty foods. Management is medical first, with dietitians helping patients stay nourished through the flares.