Endoscope image of a stomach (gastric) ulcer, a disruption of the lining of the stomach caused by digestion of the mucosa (lining membrane) by acid, pepsin and bile. This ulcer is bleeding; fresh, red blood is visible around the ulcer crater, the yellow base of which is obscured by black blood clots. Causes of gastric ulcers are related to diet, alcohol consumption, stress and certain drugs. Complications such as bleeding, perforation and obstruction due to scarring may occur. The symptoms are alleviated by antacid medicines & drugs that suppress gastric acid production; severe cases may require surgery. Stomach & duodenal ulcers are commonly called peptic ulcers.