A stomach or gastric ulcer is a small hole or erosion in the skin or in a mucous membrane such as the lining of the stomach, corroded by the acidic digestive juices which are secreted by the stomach cells. Gastric ulcers are caused by an imbalance between stomach acid, an enzyme called pepsin, and the natural defenses of the stomach’s lining. This imbalance leads to inflammation and can be worsened by aspirin and nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen. Gastric ulcer symptoms include feelings of indigestion and heartburn, weight loss, and repeated cases of bleeding in the stomach. Ulcer pain is sometimes described as gnawing, dull, aching, or similar to hunger pangs, and it usually comes and goes over long periods of time. Most ulcers are not dangerous, but when left too long they can cause internal bleeding.