Ulcer is defined as a discontinuity or presence of a break in any membrane of the body. It usually represents as a crater like sore either on the skin or on the mucous membrane. Ulcer impedes the normal functioning of that organ of which the membrane is a part. The various types of ulcers that may occur include skin ulcers (a discontinuity or break in the skin), corneal ulcer (corneal infection and inflammation leads to ulcer formation in the cornea), mouth ulcer (a break or discontinuity in the mucous membrane of the mouth), peptic ulcer (stomach ulcer), venous ulcer (a wound that occurs due to abnormal functioning of the valves present in the veins), stress ulcer (ulcer located in the stomach or beginning of duodenum), ulcerative sarcoidosis (ulceration of the skin present with sarcoidosis), and ulcerative colitis (a type of inflammatory bowel disease). The symptoms of ulcers depend on the site of their occurrence. Pain is a general symptom that is present with almost all types of ulcers.