Abstract: ObjectiveTo determine the optimal concentration and activity of rat serum in the medium for cultivating human esophageal cancer cell line.MethodsTwenty SD rats were fed with the standard diet for 30 days and then sacrificed via femoral artery bleeding and the sera were separated and collected.The sera of different concentration and activities were added into the medium for esophageal cancer cell Eca-109 culture.Methyl thiazolyl tetrazolium(MTT)assay was used to determine the optimal conditions of the sera for cultivating Eca-109 cell.Fetal bovine serum(FBS)at concentration of 10% and human normal liver epithelial cell line HL7702 were set as the serum control and the normal cell line control,respectively.ResultsUn-deactivated sera at different concentrations made Eca-109 cells grow with a exponential trend and there were significant differences in the growth of the cells between different groups at 72hr.Un-deactivated serum provided better condition for culturing Eca-109 cell and HL7702 cell than deactivated serum at the same concentration of 5% at 72hr.The serum showed the same effects on the growth of the two cell lines as the FBS.ConclusionUn-deactivated rats'serum is more suitable for cultivating Eca-109 cells than the deactivated serum at the same concentration of 5%.