An inhibitor for perioperative blood sugar elevation characterized by containing a branched amino acid, a compound which can be converted into a branched amino acid in vivo or a compound to which an amino group has been transferred from a branched amino acid. This inhibitor for perioperative blood sugar elevation is useful as a drug which is safe to the living body including human, inhibits abnormal elevation in the blood glucose level caused by anesthesia, surgery, etc., and enables proper blood sugar control, when administered to a perioperative patient.