1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is believed to induce neurotoxicity by inhibiting mitochondrial oxidative metabolism, whereas acetyl-L-carnitine (ALC) facilitates this process by transporting fatty acids into mitochondria for beta oxidation. We investigated whether large doses of ALC given by gavage for 1 week before and 1 week after MPTP could ameliorate MPTP neurotoxicity in mice. We found that ALC had no effect on MPTP-induced depletion of striatal dopamine and its metabolites.