We have conducted a cohort study of users of omeprazole and H 2 antagonists in Italy to investigate whether the peroral use of these drugs may be associated with an increased incidence of ocular disorders leading to loss of vision. We have used the Sistema Informativo Sanitario Regionale (SISR database) in Friuli-Venezia-Giulia to identify all subjects who received at least one prescription for cimetidine, famotidine, niperotidine, nizatidine, omeprazole, ranitidine or roxatidine between 1 January 1991 and 31 December 1994. We have identi®ed all hospital admissions for serious vascular or in¯ammatory ocular disorders following any such prescription, reviewed and validated all medical records. There were 71,108 users of any of the study drugs, contributing a total of 101,827 person years of observation. Seven cases of serious eye disorders were identi®ed, giving an annual incidence rate of 7/100,000 persons. By comparison to non-users, the incidence rate ratio for current users of all of the study drugs together was 0, with a 95% con®dence interval of 0 to 2.1. By comparison to non-users, the incidence rate ratio for past users was 0.47 (95% CI: 0.06±2.4). Our data are consistent with previous studies and add weight to the general impression of the ocular safety of these drugs.