[en] The clinical effect of concomitant use of non-specific immunopotentiator OK-432 and/or PSK was studied about 172 cases of primary lung cancer (Stage III, IV). In 91 cases in stage III, fifty percent survival period was found to be 11.5 months for 63 cases with OK-432 and/or PSK, and 7.5 months for 28 cases without immunotherapy, respectively. In 81 cases in stage IV, fifty percent survival period was found to be 6.7 months for 45 cases with OK-432 and/or PSK, and 3.3 months for 36 cases without immunotherapy, respectively. (author)