Intestinal bleeding. Endoscope view of bleeding (red patches) on the inner lining of the caecum, the first part of the large intestine. The bleeding is due to ruptured blood vessels in an angioma, a benign (non-cancerous) blood vessel tumour. Uncontrolled growth of blood vessels leads to the formation of the angioma, a mass of distended blood vessels that ruptures easily. If blood loss is severe, surgical treatment may be required. This includes cautery of the affected vessels or sclerotherapy, the injection of a substance that destroys them.