Three experiments were done to compare effects of LiCl and carbamazepine (CBZ) on behaviors known to be influenced by LiCl in rats. The first experiment showed acute treatment with either LiCl (0.3-1.5 mmol/kg) or CBZ (0.13-0.42 mmol/kg) to produce a learned taste aversion to saccharin. The second experiment showed short-term treatment (once daily for 5 days) with LiCl (1.5 mmol/kg/day) to suppress open field activity in otherwise untreated rats and to cause a behavioral syndrome when given together with pargyline. In contrast, short-term treatment with CBZ (0.42 mmol/kg/day) failed to influence open field behavior. The third experiment compared effects of LiCl (1.5 mmol/kg) and CBZ given at a dose (1.68 mmol/kg) higher than that used in Experiments 1 and 2. LiCl or CBZ had similar suppressant effects on locomotor activity in otherwise untreated rats, but only LiCl led to a behavioral syndrome in rats given pargyline. The findings suggest that LiCl and CBZ may have some similar mechanisms of action on behavior, as well as some different ones.