Emesis is one of the most frequent and distressing adverse effects of cytotoxic chemotherapy. Conventional antiemetic regimens are unsatisfactory due to their poor efficacy and their adverse events, particularly in children. Tropisetron (Navoban; Sandoz Pharma Ltd, Basel, Switzerland) belongs to a new class of 5-hydroxytryptamine receptor antagonists with antiemetic effectiveness in patients receiving anticancer agents. We evaluated tropisetron (0.2 mg/kg/d) in 24 chemotherapy-treated children who had experienced severe emesis during previous chemotherapy courses in spite of concomitant administration of either alizapride or metoclopramide. Complete control of emesis was achieved in 70% of the courses (37% of those including cisplatin). No severe adverse effect was reported. Headache was observed in two courses and constipation was observed during two other courses. Tropisetron proved clearly superior to conventional antiemetics and safe in use.