△⁹-Tetrahydrocannabinol (△⁹-THC), cannabinol, cannabidiol and cannabichromene were detected in commercially available cannabis seeds by silica gel TLC and gas chromatography. These cannabinoids existed in rather high content (0.10-2.02mg/100g of seeds) in the feed for birds, especially bracts (82.3-441mg/100g). When the suspension prepared from the benzene washing solution of cannabis seeds, BenW, was administered at a dose of 3mg/kg corresponding to △⁹-THC into a mouse, i.v., BenW caused hypothermia, catalepsy, pentobarbital-induced sleep prolongation and suppression of locomotor activity. These pharmacological activities of BenW were significantly higher than those of △⁹-THC (3mg/kg, i.v.). These results may indicate the necessity to reconsider the present regulations on marihuana.