We examined ten convalescent cases of local progression digestive organ cancer, which required a radical operation after a 2-week administration of preoperative dosage of PSK. Because adjuvant chemotherapy was performed for all of the cases, 3 out of 5 advanced gastric cancer patients and 4 out of 5 advanced colorectal cancer patients had more than 5-year survival. We might be effective in controlling a host immune compromise for the lap art period, which was our aim, how long preoperative PSK dosage has contributed for the extension of survival duration. We also examined the influence of the dosage in this study in preoperational of PSK, which gave a host immune compromise by the operational aggression so far, and we reported it as well.