A stomach ulcer is an open sore in the lining of the stomach, caused when digestive acid and the enzyme pepsin overwhelm the stomach’s protective mucus barrier. The most common causes are infection with Helicobacter pylori bacteria and long-term use of non-steroidal anti-inflammatory drugs such as ibuprofen; excess acid alone is rarely the whole story. Symptoms include a gnawing or burning pain between meals, nausea, and bloating, and complications can include bleeding or perforation. Diagnosis is usually by endoscopy, and treatment targets the cause: antibiotics for H. pylori, acid-suppressing medicines, and stopping the offending drugs. Dietary advice focuses on regular meals and avoiding individual triggers rather than the old-fashioned bland diet.