Cancer patients undergoing bone marrow transplantation (BMT) experience severe nausea and vomiting associated with high-dose chemotherapy agents; these emetic symptoms are compounded by total body irradiation used in many conditioning regimens. This paper reviews clinical experience with the 5-HT(3) receptor antagonist granisetron, both as a single agent and in combination with other anti-emetics, in patients undergoing BMT and peripheral blood stem cell transplantation (PBSCT). Clinical studies demonstrate the efficacy (47-61% with no vomiting and no worse than mild nausea) and tolerability of granisetron. Its long half-life and duration of action may be responsible for its effective 24 h control of nausea and vomiting in BMT patients.