A method of treating or preventing emesis through the administration of an effective dosage of a 2-(amino) tetralin compound in which one of the S or R enantiomers of the 2-(amino) tetralin compound is present in the composition in excess of the other enantiomer, and compositions comprising such a 2-(amino) tetralin compound in which the ratio of the S and R enantiomers is at least 2:1.