Effects of Phytolacca acinosa polysaccharides I (PAP-I), 5 approximately 40 mg/kg in timing of 7 times/wk, 3 times/wk and 1 time/wk on their antitumor efficiency in Sarcoma-180 bearing mice were comparatively investigated. The results confirmed that PAP-I (10 mg/kg, 3 times/wk) reached its optimal