Objective: To study the effects and mechanisms of Chinese herbal medicine—Weikangning on gastric cancer. Method: Total of 120 SD rats were divided into control group

high dose group

medium dose group and low dose group

and fed with natural saline

20

10 and 5 g/kg of Weikangning decoction respectively. The experimental animals were finally killed for the preparation of drug-containing serum. The gastric cancer cell MGC-803 was cultured with the drug-containing serum drawn from the rats in different groups. The expressions of CyclinD1

CyclinD2

Cdk4

Cdk6 and p16INK4a were detected with immunohistochemistry method-SABC. The expression of mRNA of CyclinD1

CyclinD2

Cdk4

Cdk6 and p16INK4a were detected with RT-PCR. Result: In high

medium and low dose group

the gray scales and the OPDTI value of CyclinD1 had no remarkable change;the gray scales of CyclinD2

Cdk4

Cdk6 and the OPDTI values of p16INK4a increased significantly

but the gray scales of p16INK4a and the OPDTI values of CyclinD2

Cdk4

Cdk6 decreased remarkably

compared with those in control groups. Conclusion: The Chinese herbal medicine Weikangning decoction can decrease the expressions of CyclinD2

Cdk4

Cdk6

increase the expression of p16INK4a. This effect may be involved in mechanism of gastric cancer cell growth inhibition gain by the Weikangning decoction.