Abstract: Objective To investigate the efficacy of tetramethylpyrazine(TMP) to prevent 5-fluor ouracil(5-Fu)-associated cardiotoxicity during the chemotherapy of esophageal carcinoma. Methods Patients were divided into two groups in a random manner.Both groups were treated with FLP chemotherapy.The difference between the two groups is that the former(test group) was concomitantly treated with TMP,while the latter(control group) was not given TMP.Clinical manifestation,cardiac enzyme serum levels,and electrocardiogram were recorded to evaluate 5-Fu associated cardiotoxicity.Tumor objective response rate was also recorded.Data were analyzed statistically. Results The overall incidence of cardiotoxicity in control group with treatment of 5-Fu alone is 7.9%,whereas the value was only 1.4% in 5-Fu plus TMP group (P<0.05).There was no difference in tumor objective response rate between these two groups (P>0.05).Bone marrow suppression was observed in both groups,manifested mainly by leucopenia,decrease of hemoglobin and platelet.But the severity was mild to moderate.No difference was observed between the two groups(P>0.05).Side effects on gastrointestinal tract were also observed in both groups,manifested mainly by nausea and vomiting.There was no difference between the two groups (P>0.05). Conclusion TMP is effective in preventing cardiotoxicity induced by 5-Fu.