The authors reviewed the outcome of 73 operations performed on 60 patients on long-term steroid therapy: Eighteen operations were carried out for gastro-intestinal perforation but the causal role of steroid therapy was only established in 6 cases (4 gastric and 2 colonic perforations). In the other 12 cases there was intercurrent pathology or a recrudescence of the underlying disease process. More selective indications for steroid therapy and the protective action of new drugs on the gastro-intestinal mucosa are probably responsible for the low incidence of iatrogenic complications compared with previously published series. However, steroid therapy did affect the postoperative course: the risk of infection was 20 to 30 p. 100 higher than normal, very common after emergency surgery (75 p. 100) and a major cause of mortality (60 p. 100); the risk seems to be high when the steroid dose exceeds 0.5 mg/kg/day, the disunion of an anastomosis was observed in 6 cases, including 5 "dirty" operations with a mortality of 60 p. 100, healing was slow: 2 cases of evisceration and 2 of abdominal hernia were observed. It was not possible to assess the threshold dose of steroids with regards to this complication, metabolic complications, especially adrenal failure were much less common. Of the diseases requiring steroid therapy the problem of angiitis seemed particularly prominent. Although the prognosis of the intercurrent surgical condition was not aggravated; mortality from a relapse of the angiitis was nearly 100 p. 100. Therefore, medical control of the relapse would seem to be the first priority and should be taken into account when assessing the surgical indications.