There were 12 hospital deaths in 433 patients (2.8%, 1.6% at 30 days) presenting with bleeding duodenal ulcer. Excluding patients who underwent immediate operation or early elective surgery, where ulcer size was measured at initial endoscopy rebleeding was evident in 40/288 patients (13.9%) and was associated with an increased mortality (0.4% v 12.5%) (p less than 0.0001). Rebleeding rates for ulcers less than or equal to 1 cm and greater than 1 cm were respectively 28/239 (11.7%) and 12/49 (24.5%) (p less than 0.02). Rebleeding occurred in 13/186 patients (7.0%) in whom endoscopic stigmata of recent haemorrhage were absent and in 27/102 (26.5%) with such stigmata (p less than 0.0001). The mortality rate for patients without stigmata was 3/186 (1.6%) whilst mortality figures for patients with ulcers less than or equal to 1 cm and greater than 1 cm in size were respectively 0/77 and 3/25 (12.0%) when stigmata were identified. Ulcers greater than 1 cm were more frequent in the greater than 60 year age group, more likely to have stigmata and carried an increased risk of rebleeding and mortality.