In a kindred with a familial visceral myopathy, seven patients had operations seeking relief of chronic abdominal pain and other symptoms of intestinal obstruction; one patient had an 80% cystectomy and a Y-V-plasty of the bladder neck for urinary retention. Five patients with megaduodenum had bypass operations; a side-to-side duodenojejunostomy was done in four and a retrocolic gastrojejunostomy in one. Two of these died of postoperative complications, and one developed symptomatic adhesions. Two other patients who had duodenojejunostomy have done well for 6 years and 1 1/2 years respectively. One patient with dilation of the distal jejunum and proximal ileum had relief of intestinal obstructive symptoms from jejunostomy to decompress the destal jejunum. One patient who had a resection of the descending and sigmoid colon for sigmoid volvulus has done well for four years. Three of these seven patients developed peritonitis postoperatively, and two had symptomatic adhesions after operations. Duodenal aspiration from a patient who developed postoperative peritonitis grew E. coli, 10(13) colonies per ml. After review of the results of operations in other families and in our kindred, we favor side-to-side duodenojejunostomy in megaduodenum. Duodenal aspirate must be cultured before operation. Evidence of bacterial overgrowth in the aspirate should prompt appropriate antibiotic treatment to reduce the likelihood of sepsis.