Chemotherapy treatment with combination of 5-fluorouracil and leucovorin or interferon alpha determined an incidence of severe diarrhoea of 10 and 20%, respectively. Up to date no treatment for this condition has been defined. 21 patients affected by advanced colorectal cancer and 6 patients affected by advanced pancreatic cancer received octreotide as treatment for severe diarrhoea following chemotherapy with 5-fluorouracil/leucovorin (Machover's regimen) or 5-fluorouracil/interferon (Wadler's regimen) combination. Octreotide was administered by subcutaneous injection of 50 micrograms twice daily on the first day and 100 micrograms twice daily on the second and third day. 26 patients had total cessation of diarrhoea: 4 patients within the first day, 6 within the second day and 16 within the third day. 1 patient had no change and after the last administration of octreotide he was treated with loperamide and intravenous hydration. Side effects have been mild. In summary octreotide seems to be an effective agent in the management of chemotherapy related diarrhoea.