Previous epidemiological studies have described the secular trends in peptic ulcer mortality in England and Wales as being characteristic of a cohort phenomenon. The most recent data on ulcer mortality, however, show increasing mortality rates from duodenal ulcer in women over 65 and from gastric ulcer in women over 75 years. While the rise in mortality rates in the oldest age groups is partly explained by their greater life expectancy, the increase in mortality from duodenal ulcer in older women shows evidence of an environmental (period) effect being superimposed on female cohorts born between 1895 and 1925. This effect could partly be due to the increasing consumption of non-steroidal anti-inflammatory drugs which coincides with the rise in mortality rates.