Out of all 406 people admitted to hospital with bleeding peptic ulcers over a 2-year period 230 over the age of 60 and their matched community and hospital inpatient controls were interviewed according to a questionnaire designed to obtain details of all drug intake. Non-aspirin non-steroidal anti-inflammatory drugs were taken over twice as often by the patients with bleeding as by the community controls (relative risk 2.7, 95% confidence limits 1.7-4.4) or the hospital controls (relative risk 3.8, 95% confidence limits 2.2-6.4). Confounding seemed unlikely to explain the differences, which were highly significant, were evident for both gastric and duodenal ulcer, and are likely to be important in view of the widespread use of these drugs in elderly people.