Peptic ulcer surgery during the H2-receptor antagonist era: a population-based epidemiological study of ulcer surgery in Helsinki from 1972 to 1987. To evaluate the effects of improvements in medical therapy on the incidence of, indications for and operative methods used in peptic ulcer surgery, all cases of primary peptic ulcer surgery among adults in the city of Helsinki in the years 1972, 1977, 1982 and 1987 were analysed. There was a total of 565 such cases in a population which consisted of 5.2 X 10(5) individuals in 1972 and 4.8 X 10(5) individuals in 1987. The introduction of H2-receptor antagonists in 1979 was associated with a fall in the annual incidence of elective duodenal ulcer operations, from 15.5 to 6.7 per 10(5) individuals, and a fall in the annual incidence of elective gastric ulcer operations, from 9.4 to 3.1 per 10(5) individuals (P less than 0.05). The decrease was greatest among males with duodenal ulcer. In contrast, the annual incidence of emergency surgery for ulcer haemorrhage and perforation (all types of ulcers) remained relatively stable, varying from 7.2 to 10.2 per 10(5) inhabitants over the observation period (n.s.). The mean age of patients undergoing elective surgery remained essentially unchanged. The mean age of patients undergoing emergency surgery increased. The decrease in the annual incidence of elective duodenal ulcer surgery occurred mainly in relation to proximal gastric vagotomy. There was a concomitant relative increase in the incidence of gastric resection. The types of operative procedures used in cases of pyloric, prepyloric and gastric ulcer remained unchanged over the years 1972 to 1987. 