The endogenous cannabinoid ligand anandamide (arachidonylethanolamide) inhibited the intestinal passage of a charcoal meal when administered sc in mice at doses ranging from 0.1 to 50 mg/kg. This effect was prevented by the cannabinoid CB1 receptor antagonist SR141716A [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2, 4-dichlorophenyl)-4-me thyl-1H-pyrazole-3-carboxamide x HCl](1 mg/kg sc), but it was not affected by the anandamide transport inhibitor, N-(4-hydroxyphenyl) arachidonylethanolamide (AM404)(50 mg/kg, sc). The results indicate that anandamide modulates intestinal motility in mice by activating cannabinoid CB1 receptors. They also suggest that anandamide transport, which was previously shown to participate in terminating neural and vascular responses to anandamide, does not contribute to anandamide inactivation in intestinal tissue.