To assess changes in the pattern of admission and operation for duodenal ulcer in Scotland, data recorded on Scottish Medical Records forms for the years 1975-1990 were analysed. The overall admission rate fell by 38 per cent from 157 to 98 per 100,000 population while the number of operations per year dropped by 80 per cent from 2955 to 582. There was a decline in perforation rate between 1975 and 1990 from 27 to 15 per 100,000 population. This general trend conceals a significant 93 per cent increase in the incidence of duodenal ulcer perforation among women aged 65 years and above, from 21 per 100,000 in 1975 to 41 per 100,000 in 1990 (r = 0.76, P < 0.001). There was a general trend towards a decline in haemorrhage rates, although this was significant only for men aged 15-44 years (r = -0.73, P < 0.01) and 45-64 years (r = 0.63, P < 0.04).