The other two trials (Trials 3 and 4) enrolled subjects who were experiencing nausea and vomiting after surgery. In Trial 3, subjects did not receive any medication to prevent nausea and vomiting before surgery and in Trial 4 they received the medication, but the treatment did not work. In both trials, subjects were randomly assigned to receive either amisulpride or placebo. Neither the subjects nor the health care providers knew which treatment was being given until after the trial was complete.