Eighteen patients with post-operative enterocutaneous fistulas were treated with total parenteral nutrition (TPN), skin care, infection control and intravenous somatostatin (SMS) 250 micrograms/h. This group was compared with 30 patients treated with standard medical treatment (total parenteral nutrition (TPN), skin care and infection control). In the SMS group the fistula output was reduced to 50% in three days and spontaneous closure was observed in 14 patients after a mean of 6.1 +/- 3.1 days of treatment with SMS, and in 18.2 +/- 6.3 days after the TPN administration. In the control group the fistula output was reduced by up to 50% after a week and spontaneous closure occurred in 20 patients in a mean of 27.4 +/- 8.7 days after the start of treatment. These results are statistically significant. There was one (5.5%) death in the SMS group compared with three (10%) deaths in the other, and glucose intolerance was observed in two (11%) patients in the SMS group. Somatostatin has been shown to be useful in the conservative treatment of enterocutaneous fistulas because of its ability to reduce output and accelerate closure.