Ricasetron (BRL-46470) is a drug which acts as a selective antagonist at the serotonin 5-HT<sub>3</sub> receptor. It has antiemetic effects as with other 5-HT<sub>3</sub> antagonists, and also has anxiolytic effects significantly stronger than other related drugs, and with less side effects than benzodiazepine anxiolytics. However, it has never been developed for medical use.