Abstract: Objective To study killing effects of different dosage regimens of Gefitinib in combination with Cetuximab on Lovo cells(human colorectal cancer cell line)for exploring effects of Gefitinib and Cetuximab alone or combined on colorectal cancer.Methods Colorectal cancer cells were selected by direct sequencing of products after PCR amplification.Inhibiting effects of Gefitinib and Cetuximab of different times,concentrations and administration orders on Lovo cells with no K-ras mutation were evaluated by determination of combined effects of both drugs.Influence of optimal dosage regimen on cell cycle distribution and apoptosis rate of Lovo cells was determined by flow cytometry.Results Iit was confirmed that both Gefitinib and Cetuximab could induce apoptosis,and inhibitive effects of Gefitinib in combination with Cetuximab on Lovo cells were significantly stronger than that of Gefitinib or Cetuximab alone;However,different times,concentrations and administration orders of both agents did no produce significant difference(P>0.05).Conclusion Gefitinib in combination with Cetuximab could produce inhibitive effects on proliferation of Lovo cells.