Effects of streptococcal preparation OK-432 on chemically-induced intestinal carcinoma in rats.

Intestinal tumors were induced by repeated subcutaneous injection of 1,2-dimethylhydrazine in Donryu strain rats for 28 weeks. A streptococcal preparation, OK-432 was administered at different times of the tumor induction_ Between the OK-432 treated and the untreated groups no significant difference was observed in the incidence of intestinal tumors, the total number of tumors per rat, the location of tumors, or the survival time. Though low incidence of extra· intestinal malignancies in the OK-432 treated animals seemed to be the only positive finding, it was not statistically significant.