Objective To explore the possible mechanism of Xiaozheng Decoction（ 消癥汤） inhibiting recurrence of bladder cancer. Methods Bladder cancer T24 cells of logarithmic phase were extracted. The concentration after regulating was 1 × 10

4

cells / ml. The cells were inoculated in 96-well plates

200μl in each pore. After 24 hours of routine culture

complete medium 200 μl containing Xiaozheng Decoction in different concentration（ with final concentration of drug 5

10

20

40

80

160

320

640

or 1280μg / ml） was added to each pore. Five parallel pores of each concentration were designed. After intervention for 24 hours

the inhibition effect of Xiaozheng Decoction on T24 cell multiplication was examined with methyl thiazolyl tetrazolium（ MTT） method. The Xiaozheng Decoction concentration of median lethal dose( IC

50

) was calculated. According to the results

T24 cells were cultured with low

medium and high dose of Xiaozheng Decoction for 24 hours. 0 μg / ml of Xiaozheng Decoction was designed as control. The impact of Xiaozheng Decoction on T24 apoptosis was examined with Annexin V / propidium iodide（ PI） double staining method. The expressions of Slit2

Bim

and Bad proteins and genes in the low

medium and high dose groups were detected with Western blot and reverse transcriptase-polymerase chain reaction（ RT-PCR） methods. Results IC50 of Xiaozheng Decoction to T24 cells was 127. 14μg / ml

120μg / ml of medium dose

60μg / ml of low dose

and240μg / ml of high dose. The percentage of apoptotic cells of T24 cells in the control group was（ 4. 41 ± 0. 50） %

（ 4. 47 ± 0. 13） % in the low dose group

（ 11. 04 ± 1. 32） % in the medium group

and（ 12. 08 ± 0. 55） % in the high dose group. Compared with the control group

the percentage of apoptotic cells in the medium and high dose groups increased（ P

<

0. 05 or P

<

0. 01）. Compared with the low dose group

the expressions of Slit2

Bim

and Bad proteins and genes which were related to apoptosis in the medium and high dose groups increased（ P

<

0. 05）.Conclusion Xiaozheng Decoction might inhibit the proliferation of bladder cancer T24 cells. It might be related to increasing the expressions of apoptosis related proteins

such as Slit2

Bim and Bad.