Abstract: Objective To explore effects of water extract of radix salviae miltiorrhizae on renal injury in rats exposed to cadmium and its possible mechanism.Methods Twenty male and female healthy Wistar rats,respectively,at age of 6 weeks were randomly divided into blank group (n =8),and model group (n =32) after adaptive feeding for 1 week,given intraperitoneal injection of saline for 5 mL/(kg · d) and intraperitoneal injection of cadmium chloride solution for 2.8 mg/(kg · d).Continuously building for 4 weeks,the general situation of rats was observed,and the rat kidney function and kidney tissue pathological changes were detected.After successful molding,the model group was randomly divided into medicine group,negative and positive and blank control groups.The medicine group was given Salvia miltiorrhiza water extract of high dose of 2.7g/(kg · d),Danshen aqueous extract of low dose 1.35 g/(kg · d) by gavage,positive control group was given sodium selenite for 0.05 mg/kg · d by gavage,the negative and blank control groups were given the same mount of saline for 2.7 mL/(kg · d).After 10 weeks of treatment,serun and urine was collected,and kidney tissue was to be detected.Results Salvia miltiorrhiza water extraction liquid of low and high dose group had less 24 h urine volume than negative control group,and serum superoxide dismutases (SOD) increased significantly,Malondialdehyde (MDA) decreased significantly,total antioxidant capacity (T-AOC) increased significantly,blood urea nitrogen,urinary beta β2-MG content and serum creatinine levels was decreased.Pathological section revealed that renal proximal convoluted tubules epithelial cells was turbid,swelling,degeneration and necrosis in the negative control group.Salvia miltiorrhiza water extraction liquid of low and high dose group had lower serum cortical cadmium content than the negative control group,Salvia miltiorrhiza water extraction liquid of low and high dose group had lower apoptosis rate than the negative control group.Conclusion The salvia miltiorrhiza water solution can accelerate the metabolism of cadmium,and effectively interfere with cadmium induced renal injury,delay chronic renal failure,and protect the kidney.