The present invention provides an anti-tumor pharmaceutical composition having a high anti-tumor effect with low side-effects. The anti-tumor pharmaceutical composition comprises a N-vanillyl fatty acid amide of formula (1): ##STR1##

wherein —CO—R group represents a saturated or unsaturated fatty acid residue containing from 14 to 32 carbon atoms. Accordingly the invention provides an anti-tumor pharmaceutical composition comprising a N-vanillyl fatty acid amide which relates to capsaicin wherein the composition has a low side-effect and a high anti-tumor effect, in particular an anti-melanoma effect and an anti-leukemia cell effect; and is very low pungent, stimulatory and preinflammatory effect.