© 2003 European Society for Medical Oncology Prevention of irinotecan plus

diarrhoea by oral administration of neomycin plus bacitracin in first-line treatment of advanced colorectal cancer Irinotecan (CPT-11) plus 5-fluorouracil/leucovorin (5-FU/LV) regimen is at present employed as first-line chemotherapy for advanced colorectal cancer (CRC). Its clinical use is associated with an elevated incidence of diarrhoea (∼60–70%). Diarrhoea is the dose-limiting toxicity of this regimen and sometimes represents a serious adverse event [1]. Recently, the role of the intestinal bacterial microflora in the etiopathogenesis of the CPT-11-induced intestinal toxicity has been discovered. The active metabolite of CPT-11, SN38, is generated from CPT-11 by sieric carboxylesterase, and subsequently conjugated to SN38-G by hepatic UDP-glucuronyltransferase. SN38-G is the inactiv