The effects of low-molecular-weight-chitosan(LMWC) on chronic renal failure(CRF) rats induced by adenine were investigated in vivo and in vitro. Chitosan were hydrolyzed using chitosanase at p H 6–7 and 37 for 24℃ h to obtain LMWC. In vitro, the effect of LMWC on the proliferation of renal tubular epithelial cells(RTEC) showed that it had no cytotoxic effect and could promote cell growth. For the in vivo experiment, chronic renal failure rats induced by adenine were randomly divided into control group, Niaoduqing group, and high-, medium- and low-dose LMWC groups. For each group, we detected serum creatinine(SCR), blood urea nitrogen(BUN), and total superoxide dismutase(T-SOD), glutathione oxidase(GSH-Px) activities of renal tissue, and obtained the ratio of kidney weight/body weight, pathological changes of kidney. The levels of serum SCR, BUN were higher in the adenine-induced rats than those in the control group, indicating that the rat chronic renal failure model worked successfully. The results after treatment showed that LMWC could reduce the SCR and BUN levels and enhance the activities/levels of T-SOD and GSH-PX in kidney compared to control group. Histopathological examination revealed that adenine-induced renal alterations were restored by LMWC at three tested dosages, especially at the low dosage of 100 mg kg-1 d-1. The effects of low-molecular-weight-chitosan (LMWC) on chronic renal failure (CRF) rats induced by adenine were investigated in vivo and in vitro. Chitosan were hydrolyzed using chitosanase at p H 6-7 and 37 for 24 ° C h to In vitro, the effect of LMWC on the proliferation of renal tubular epithelial cells (RTEC) showed that it had no cytotoxic effect and could promote cell growth. For the in vivo experiment, chronic renal failure rats induced by adenine were randomly divided For each group, we detected serum creatinine (SCR), blood urea nitrogen (BUN), and total superoxide dismutase (T-SOD), glutathione The levels of serum SCR, BUN were higher in the adenine-induced rats than those in control groups, indicating that the ratio of kidney weight / body weight, pathological changes of kidney that the rat chronic renal failure model worked success fully. The results after treatment showed that LMWC could reduce the SCR and BUN levels and enhance the activities / levels of T-SOD and GSH-PX in kidney compared to control group. Histopathological examination revealed that adenine-induced renal alterations were restored by LMWC at three tested dosages, especially at the low dosage of 100 mg kg-1 d-1.