A gastric ulcer is a disintegration of the stomach lining which interferes with the production of the mucous that coats the lining allowing stomach acid to come in contact with the stomach. This causes pain to the patient after eating, which encourages the production of stomach acid. Given time, the acid can eat right through the lining, exposing the capillaries beneath, leading to a bleeding gastric ulcer, which increases the pain. If left unattended, the ulcer can become perforated, leading to peritonitis and sepsis, either of which is life threatening.