The glucose antimetabolite 2-deoxy-D-glucose (2DG) reliably causes hyperphagia in rats, but has consistently proven ineffective in producing overeating in golden hamsters. It was hypothesized that hamsters do not overeat following 2DG administration because of unusually strong aversive effects of the drug in this species. To test this hypothesis, rats and hamsters were tested in a conditioned taste aversion (CTA) paradigm, in which a novel 0.1% saccharin solution was paired on three occasions with intraperitoneal injections of either saline, lithium chloride (LiCl; 50 mg/kg), or 2DG (either 350 or 750 mg/kg). CTA was measured in 16 twenty-minute, two-bottle preference tests which were conducted at 2-3 day intervals following conditioning. LiCl and 2DG both produced strong and long-lasting aversions to saccharin solution in rats. However, 2DG was significantly less effective than LiCl in producing CTA in hamsters. It is unlikely, therefore, that the failure of 2DG to produce hyperphagia in hamsters is due primarily to an unusual sensitivity to the aversive effects of the drug.