The synthesis of fully deuterated amphetamine (phenyl-2-aminopropane-d11) in which 11 deuterium atoms are bonded to carbons and two other highly deuterated analogues is described. Their toxicities and in vivo spontaneous locomotor activities in mice were examined and compared with that of the parent protioamphetamine. A significant reduction in toxicities and a decrease in spontaneous locomotor activity were observed for these highly enriched deuterated analogues, as compared to protioamphetamine.