A comparative clinical study was conducted with an addition of vitamin A added to the auxiliary chemotherapies after surgical operation of gastric cancer. The OK-432 + MMC + Tegafur therapy (hereafter referred to as Group A) and the OK-432 + MMC + Tegafur + vitamin A therapy (Group B) were administered. The results were as follows. 1) The survival rate was slightly higher in Group B, although there was no significant difference between the two. 2) As to the rate of recurrence, it was significantly lower in Group B (p less than 0.05). The results above have suggested that additional vitamin A to the auxiliary chemotherapies after operation of gastric cancer can possibly be lower the recurrence rate, contributing to the prolongation of life.