Objective: To approach the effect of Changweiqin (CWQ) drug serum associated with oxaliplatin on the proliferation and apoptosis of human colon cancer resistant cell lines HCT116/L-OHP. Method: To investigate the growth and inhibition of HCT116/L-OHP treated with Oxaliplatin (L-OHP) and CWQ drug serum in HCT116/L-OHP by MTT assay

analyze the cell cycle distribution by flow cytometry propidium iodide (PI) staining

and monitor its apoptosis by Annexin V-FITC kit. Result: Oxaliplatin resistance index to HCT116/L-OHP is 9.17.The IC50 value of Oxaliplatin in 48 hours when treated to HCT116 and HCT116/L-OHP respectively is (9.88±0.42) mg·L-1 and (85.81±2.76) mg·L-1. After connected with CWQ drug serum

the IC50 value decreased to (35.2±2.8) mg·L-1

and the reverse index is 2.44(P<0.05). The cell cycle which treated before and after Oxaliplatin associated with CWQ respectively arrested at the G1

G2 phase and G1 phase. The P value between each group in G1 and G2 phase are all less than 0.001.The P value between each group in S phase are all less than 0.001 while the P value between Oxaliplatin treated with CWQ group and Oxaliplatin group is equal to 0.021.The apoptosis rate of HCT116/L-OHP were(8.6 ± 0.31)% and (23.73 ± 2.36)% respectively. The P value is equal to 0.037 when Oxaliplatin group is compared with blank group. The P value of Oxaliplatin group compared with blank group is equal to 0.046

while the P value of others is less than 0.001. Conclusion: CWQ drug serum can reverse the resistance of Oxaliplatin to human colon cancer cell lines HCT116/L-OHP

induce cells' apoptosis and change the cell cycle's distribution.