Colitis. Gross specimen of an excised section of colon showing numerous ulcers in colitis. This is an inflammation of the colon that leads to bloody diarrhoea, swelling of the intestine and an increased risk of developing colon cancer. Treatment is usually with anti-inflammatory drugs, although drugs that suppress the immune system are also effective. If the condition resists drug treatment then all or part of the colon can be surgically removed.