Anandamide (arachidonylethanolamide), an arachidonic acid derivative isolated from the porcine brain, displays binding characteristics indicative of an endogenous ligand for the cannabinoid receptor. The functional activity of anandamide was tested in vivo using behavioral and physiological paradigms in laboratory rodents. At IP doses from 2 to 20 mg/kg in mice, anandamide significantly decreased spontaneous motor activity in a Digiscan open field. Rectal body temperature significantly decreased at doses of 10 and 20 mg/kg in rats. At doses from 0.03 to 30 mg/kg, anandamide had no significant effect on chow consumption in ad lib fed rats. Over the dose range of 2-20 mg/kg, anandamide did not show anxiolytic properties in the mouse light<-->dark exploration model of anxiety. Over the dose range of 0.3-3 mg/kg, anandamide had no effect on choice accuracy or session duration in the delayed nonmatching to sample memory task (DNMTS) in rats. These results demonstrate that anandamide has biological and behavioral effects in awake rodents, some of which are similar to the reported actions of THC.