The anti-emetic effect of a 5-HT$_3$ receptor antagonist, Ondaron, was compared with that of the approved ondansetron agent, Zofran$circledR$ in the ferrets. Emesis was induced by single intraperitoneal injection of cisplatin 10 mg/kg, and Ondaron or Zofran$circledR$ was injected intraperitoneally in a dose of 1.0 mg/kg, respectively. Ondaron and Zofran$circledR$ effectively antagonised the emetic response for 4 hours after injection. They significantly reduced the number of vomiting and retching, and prolonged the latency to the first episode. The anti-emetic effect of Ondaron was almost the equal to that of Zofran$circledR$. These results suggest that Ondaron is an effective anti-emetic agent against cisplatin-induced emesis, and its anti-emetic potency is similar to that of 5-$HT_3$ receptor abtagonist, Zofran$circledR$.