An antiemetic and NK1 antagonist (Ki = 3 nM; IC50 = 0.09 nM for the human receptor); selective for NK1 over NK3 receptors (Ki = 454.1 nM for human NK3); prevents substance P-induced plasma extravasation into the esophagus of guinea pigs at 1 mg/kg; reduces NK1-agonist-induced foot tapping in gerbils