Twenty-one women with slow-transit constipation have been treated by bowel resection. All had a normal barium enema, but an increased colonic transit time. Pathological examination of the resected colons showed no evidence of aganglionosis. Some of the patients were treated by segmental colonic resection, anorectal myectomy, anal stretch or internal sphincterectomy but were not helped. Colectomy with ileorectal or caecorectal anastomosis gave the best results; on balance, ileorectal anastomosis seems preferable. Of sixteen patients who underwent colectomy, ten subsequently had normal bowel function and four were markedly improved. The spontaneous bowel frequency in this group rose from 0.3 +/- 0.1 (s.e.m.) to 21.7 +/- 8.3 weekly (P less than 0.001).