A peptic ulcer is an erosion in the lining of the stomach or duodenum where acid and pepsin overwhelm mucosal defences, causing gnawing pain, often worse when the stomach is empty. The great majority are caused by Helicobacter pylori infection or by non-steroidal anti-inflammatory drugs (NSAIDs); the old story of stress and spicy food as primary causes has been retired, though they can aggravate symptoms. Complications include bleeding, perforation, and obstruction, all potentially life-threatening. Treatment eradicates H. pylori with antibiotics, suppresses acid with proton pump inhibitors, and withdraws NSAIDs where possible. Dietary management is supportive rather than curative: regular meals, avoidance of alcohol and individual trigger foods, and adequate nutrition during healing, with no need for the bland milk diets once prescribed.