In a blind crossover trial for 4 days, after at least 7 days on conventional treatment, 14 patients with postoperative small-bowel fistula were randomised to 2 days on a somatostatin analogue, octreotide (SMS 201-995), followed by 2 days on placebo (group 1) or vice versa (group 2), after which all patients were treated with octreotide until the fistula closed or reoperation was deemed necessary. In group 2 mean fistula output was reduced from 698 ml per 24 h pretreatment to 246 mg per 24 h after 2 days on octreotide; output increased from 228 ml per 24 h to 497 ml per 24 h when treatment with octreotide was interrupted by placebo. In 11 patients fistulae closed spontaneously in an average of 4.5 days after continous treatment with octreotide.