Methods, compositions, systems, and packaging are disclosed for reducing postoperative nausea and/or vomiting (PONV) in a human patient in need of general anesthesia for surgery. Such methods may include scheduling a surgery for the human patient, and administering to the patient one or more series of prescribed medicines for at least three successive days during a regimen immediately preceding general anesthesia. Compositions may include cholinergic receptor agonists, muscarinic receptor agonists, dopamine receptor agonists, MAO inhibitors, serotonin receptor agonists, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, selective serotonin releasing agents, serotonin-norepinephrine-dopamine reuptake inhibitors, opioids, or analgesics.