Objective: To investigate the effect of Tongluotangtai decoction on 5-HT, β-EP, histamine and bradykinin in serum of STZ rats with pain-related diabetic neuropathy. Methods: The rat model of diabetic peripheral neuropathy was made by intraperitoneal injection of STZ. The rats were divided into control group, model group, Tongluo sugar group and phenytoin. The rats were administrated with saline, Tongluo sugar Thai or phenytoin sodium daily, and the levels of 5-HT, β-EP, histamine and bradykinin in the serum of each group were measured after 3 w, 5 w and 9 w. Results: After 3 w, 5 w and 9 w of drug intervention, the levels of 5-HT, histamine and bradykinin in the model group were significantly higher than those in the control group (P<0.05) and the level of β-EP was significantly reduced. Compared with the model group, the contents of histamine and bradykinin in Tongtao Tangtai group and phenytoin group were significantly decreased and the level of β-EP was significantly reduced. Compared with the rats in the phenytoin group, the contents of histamine and bradykinin in Tongtao Suantai group and phenytoin group were significantly decreased and the level of β-EP was significantly reduced. Conclusion: Tongtao Tangtai decoction can significantly reduce the level of 5-HT, histamine and bradykinin in STZ-induced diabetic neuropathy model rats, increase the content of β-EP and exert a significant anti-pain effect.