Peptic ulcers form in the lining of the stomach, esophagus, or small intestine. Around 80% of ulcers are caused by Helicobacter pylori bacteria. Symptoms include abdominal pain, nausea, and vomiting of blood. Diagnosis involves tests to detect H. pylori infection and endoscopy to view the ulcers. Treatment focuses on eliminating H. pylori with antibiotics and reducing acid with proton pump inhibitors or H2 blockers to promote healing. Lifestyle changes and medications that protect the stomach lining can also help treat peptic ulcers.