Many BRMs (biological response modifiers) have been used for post-operative immunochemotherapy. And their usefulness were also reported. Nevertheless it is still unknown that which route, how much doses and which timing are the most effective to administer these drugs. We used BRMs intratumorally and preoperatively. To reconfirm the efficacy of intratumoral injection therapy randomized study was performed in gastric carcinoma. Three hundred and ninety-five cases were entered, 199 cases in group A which were treated preoperatively with OK-432 intratumorally and 196 cases in group B which were control, respectively. In the cases which had marked infiltration of lymphoid cells in tumor sites, the two year survival rate of group A was significantly better than that of group B (p less than 0.05). On the study of recurrent forms, the distal lymph node metastasis was markedly decreased in group A. The ratio of metastasis to the distal lymph nodes in group A was 5-10% lesser than that in group B on the each depth of tumor invasion. The ratio of lymph nodes metastasis was almost similar in the each group, but the number of metastatic lymph nodes was significantly reduced in high grade tumor infiltrated cases in group A (p less than 0.005). These results suggest that preoperative endoscopically intratumoral administration of OK-432 suppresses the lymph node metastasis and improves the postoperative survival rate.