OBJECTIVE: To explore the effect of angelica polysaccharide (AP) on the thymocyte proliferation and RBC C3bR immune adhesion function in radiated mice. METHODS: Mice were divided into control, irradiated and AP treated also irradiated groups (10 per group). The proliferation of thymocytes and RBC C3bR rosette formation rate were then examined on day 10 after AP was given. RESULTS: The thymocyte proliferation responses (0.24±0.01) and the RBC C3bR rosette formation rate ［(16.46±0.76)%］ of the irradiated control group were significantly lower than those of the non irradiated controls ［(0.35±0.01) and (22.30±1.26)%, respectively; P<0.01］］. The thymocyte proliferation (0.31±0.01) and RBC 36bR rosette formation ［(21.07±1.22)%］ in the treatment group were significantly higher (P<0.01) than those of the irradiated control group, and approached nonirradiated control levels. CONCLUSIONS: AP can reverse radiationinduced reduction in the proliferation response of thymocytes and in RBC immune adhesion function.