Twenty-two heroin addicts admitted with an acute abdomen to the surgical department in the years 1971-1981 were reviewed. Fifteen patients had symptoms suggesting intestinal obstruction, 7 proved to have pseudo-obstruction, 4 had withdrawal symptoms, 2 had faecal impaction and only 2 had adhesions which necessitated operation. A haematocrit level of more than 0.46 was found to be indicative of true obstruction. Frequently, elevation of the white blood cell count or erythrocyte sedimentation rate merely reflected a state of accompanying soft tissue infections which were very common in these patients. The remaining 7 patients were admitted with intra-abdominal inflammation, 2 patients had an appendix mass, 1 had gonococcal peritonitis, 3 had appendicitis and 1 had a normal appendix removed. In these 7 patients the history and physical findings were characteristic of the suspected pathology.