Relaparotomy occurs commonly in patients with the Peutz-Jeghers syndrome, and at quite short intervals. Between 1943 and 1987 laparotomies were performed on 54 occasions in 23 patients with the Peutz-Jeghers syndrome who at some time came under the care of St. Mark's Hospital. In four patients repeat laparotomy was performed within a single year. Between 1987 and 1989 a further five patients have undergone laparotomy with on-table small bowel endoscopy. External palpation and small bowel transillumination failed to demonstrate 17 out of a total of 45 hamartomas (38 per cent). Of these 17 polyps identified endoscopically, 11 (65 per cent) were sufficiently large that a snare was used to remove them. We recommend peroperative enteroscopy as an adjunct to surgery in the Peutz-Jeghers syndrome.