A method for preventing, inhibiting or treating nausea and/or vomiting in a mammalian subject, the method comprising administering an effective amount of a peripherally-restricted kappa opioid receptor agonist to the subject. The nausea and/or vomiting can be associated with use of an opioid, such as morphine or fentanyl. The peripherally-restricted kappa opioid receptor agonist can be an L-amino acid-containing peptide, a D-amino acid-containing peptide, or a synthetic peptide amide, such as for instance, D-Phe-D-Phe-D-Leu-D-Lys-[ω(4-aminopiperidine-4-carboxylic acid)]-OH (CR845).
