PURPOSE: The purpose of the study was the evaluation of efficacy and the side effects of irinotecan in treatment of advanced colorectal cancer. METHODS: The authors presented their experiences with irinotecan in the treatment of 10 patients suffering from advanced colorectal cancer. The dose of irinotecan was 350 mg/m(2) every 21 days. Seven out of ten patients have taken oral fluoroquinolon to investigate its effect on the incidence of febrile episodes in case of febrile neutropenia. Three out of ten patients did not receive any antibiotic. The authors have examined the efficacy and safety of the treatment. RESULTS: One complete remission was obtained. Authors describe the observed side effects and the administered supportive care against serious complications. DISCUSSION: Serious diarrhoea has not been found in case of these 10 patients. The diarrhoea caused by irinotecan can be stopped by loperamide. The authors give accounts of early and following results.