We examined the effect of alpha-tocopheryl hemisuccinate (TS) on the growth of mouse melanoma cells B16-F1 inoculated on the back of hairless mice by two administration procedures of TS, i.p. administration of TS dissolved with dimethyl sulfoxide (TS i.p.) and i.v. administration of TS vesicles (TS-vesicle i.v.). TS i.p. significantly prevented the tumor growth of only half the mice in the group. However, TS-vesicle i.v. almost completely inhibited the tumor growth of all mice. Furthermore, the mean survival of the TS-vesicle i.v. group was 1.4-fold those of the control and TS i.p. groups.