Presented are pharmaceutical carcinostatic compositions comprising as active ingredient a diol represented by the formula: ##STR1## wherein n is an integer of 6 to 33; or by the formula: ##STR2## wherein R is hydrogen or C.sub.1 to C.sub.5 alkyl and m is an integer of 3 to 21; and methods of treatment of cancer of animals with a diol represented by the above formulas. The compositions and the methods are useful for cancer treatment without causing side effects.