This open label pilot study evaluated the safety and efficacy of the oral 5-HT3 receptor antagonist granisetron for prophylaxis of delayed chemotherapy-induced nausea and vomiting (CINV) in 30 patients with advanced or recurrent colorectal cancer. Patients were studied during two cycles of a 5-week regimen with irinotecan (CPT-11) and UFT. Patients received prophylactic anti-emetic therapy that included intravenous granisetron. If Grade 1 or higher severity gastrointestinal symptoms occurred during 6 days after CPT-11 administration in Cycle 1, then oral granisetron was administered daily for the following 5 days of CPT-11 in Cycle 2. Sixteen patients (53.3%) experienced delayed CINV in Cycle 1. The incidence of Grade 2 or higher vomiting was 32.1% and 27.7% in Cycles 1 and 2 in males (P = 0.554) respectively, and 54.6% and 32.4% in females (P = 0.001) respectively. Granisetron is effective against delayed Grade 2 or higher vomiting induced by CPT-11/UFT in female patients, although granisetron alone may not sufficiently control nausea induced by this regimen.