Abstract: OBJECTIVE To explore the pathogen distribution and its effects on serum Smad signaling transduction related proteins in infected cerebrocardiac syndrome patients, so as to provide reference for clinical diagnosis and treatment. METHODS A total of 170 cases of infected cerebrocardiac syndrome patients in our hospital from Oct. 2009 to Apr. 2015 were enrolled in this investigation. The isolated pathogens were identified by PHOENIX TM100 equipment and the serum related factors including Smad signaling pathway related proteins, Smac and S100B were assayed by ELISA. Another 170 cases of healthy subjects and 170 cases of non-infected cerebrocardiac syndrome patients were taken as control in our hospital at the same period. RESULTS Totally 170 stains of pathogens were identified from the 170 infected patients. The pathogens contained 82 (48.2%) strains of gram-positive bacteria and 88 (51.8%) strains of gram-negative bacteria. The gram-positive bacteria mainly were 20 strains of type F hemolytic Streptococcus and 15 strains of Streptococcus pyogenes, accounting for 11.8% and 8.8%. The gram-negative bacteria mainly were 22 strains of Enterobacter cloacae and 14 strains of Klebsiella pneumonia, accounting for 13.0% and 8.2%. The results also revealed that the serum TGFβ, Smad1, Smad2, Smad3 and Smad5 were increased greatly in infected patients while the Smac, S100B and β-amyloid were decreased dramatically in infected patients(P<0.05). CONCLUSION Cerebrocardiac syndrome patients are suffered from pathogen infection, and the abnormal expressions of Smad signaling transduction pathway, S100B and Smac proteins are involved in this pathological process.