PURPOSE: To provide the subject medicine highly effective and free from significant side effects, useful for cancer patients with high anti-Mycobacterium tuberculosis immunity.

CONSTITUTION: The objective medicine, useful for cancer patients with high anti-Mycobacterium tuberculosis immunity developed by BCG inoculation or the inoculation of pertussis vaccine as adjuvant, contains, as active ingredient, (A) BCG-extracted polysaccharides consisting mainly of those composed of arabinose and mannose and having specificity to high tuberculosis immunity or (B) human-type Mycobacterium tuberculosis-extracted polysaccharides having the same immunological characteristics as those of BCG. This medicine gives high efficacy at a very low dose, and can also be administered continuously for a long period of time because of absence of factors inducing side effects.