Based on studies of the antioxidative activity of lipids (aoa) of the organs and tissues of tumor-bearing animals during tumor growth, it is suggested to use the following schedule of combined chemotherapy of tumors: at early terms of tumor progression, when the level of aoa in the organs of a tumor-bearing animal is maximum, to inject alkylating agents which sharply reduce the aoa level, when their level in tissue is low to inject synthetic antioxidants which raise it.