SN instructed patient about on gastric ulcer. Gastric ulcers occur on the inside of the stomach. Pain is the most common symptom. The pain is caused by the ulcer and is aggravated by stomach acid coming in contact with the ulcerated area. The pain typically may: Be felt anywhere from your navel up to your breastbone. Be worse when your stomach is empty. Flare at night. Often be temporarily relieved by eating certain foods that buffer stomach acid or by taking an acid-reducing medication. Disappear and then return for a few days or weeks. See your doctor: If vomiting of blood — which may appear red or black. Dark blood in stools or stools that are black or tarry. Nausea or vomiting. Unexplained weight loss. Appetite changes.