Ramosetron is a serotonin 5-HT3 receptor antagonist for the treatment of nausea and vomiting. It is believed to have higher potency and longer antiemetic action than other 1st generation 5-HT3 antagonists such as ondansetron. Ramosetron is also indicated for a treatment of “diarrhea-predominant irritable bowel syndrome in males”. It is only licensed for use in Japan and selected Southeast Asian countries.