Objective      To study the therapeutic effect of cinobufagin on bladder cancer.       Methods      Fifty SD rats were randomly divided into experimental group (n=40) and control group (n=10). N-methyl-N-nitrosourea (N-MNU) was infused into bladder of rats in experimental group (2.5 mg every 3 weeks

for 4 times)

and after that

the rats of later group were divided into saline group

mitomycin group (5 mg/kg)

low dose cinobufagin group (5 mg/kg) and high dose cinobufagin group (20 mg/kg)

into which saline

mitomycin

low and and high dose cinobufagin were infused

once a week

for 5 times. Tumor-inhibiting rate of cinobufacin was calculated and apoptosis of tumor cells was detected by TUNEL assay.       Results      The animal bladder tumor model was successfully established by infusing N-MNU into bladder. The tumor-inhibiting rate was 76.7% and the apoptosis index (AI) was （24.21±1.24）% in high dose cinobufotalin group

which were significantly higher than those in low dose cinobufotalin group and mitomycin group (P0.05).       Conclusion      Cinobufagin can inhibit the growth of bladder tumor in SD rats

and promote apoptosis of bladder tumor cells. The higher the cinobufotalin level is

the stronger the apoptosis-promoting effect of cinobufotalin is.