Objective To determine the endogenous metabolites in blood of rats with Xiaoqinglong Decoction Syndrome by using GC-MS;To provide evidence for researches on the essence of Xiaoqinglong Decoction Syndrome. Methods Totally 36 male Wistar rats were randomly divided into blank control group (10 rats), model group (13 rats), and Xiaoqinglong Decoction group (13 rats). Model group and Xiaoqinglong Decoction group were used to make the models of exogenous cold and internal fluid syndrome (Xiaoqinglong Decoction Syndrome). Rats in Xiaoqinglong Decoction group received gavage with Xiaoqinglong Decoction, while rats in blank control group received nothing. Blood of rats in the three groups was taken from the abdominal aorta and detected by GC-MS 15 days later, and analyzed by multivariate statistical analysis with PLS-DA. Results 13 kinds of biomarkers were found:lactic acid, 3-hydroxy-butyric acid, glycine, serine, lysine, dextrose, arachidonic acid and other metabolites. Conclusion Expressions of biomarkers, such as lactic acid and glycine, are energy metabolism, immune function, and inflammation, which provide material basis for researches on the essence of Xiaoqinglong Decoction Syndrome.

Through the map analysis of various metabolites in rat's urine, the biomarkers in syndrome suitable for Small Qing-Long Decoction (SQLD) were found out, which provided objective basis for the clinical diagnosis and treatment. Based on the rat's urine nuclear magnetic resonance (NMR) spectrum detection of the blank control group, the model group and the SQLD group, the data come from the map by MestRenova pretreatment and integration were analyzed using SIMCA-P+ by (PLS-DA). Then, the corresponding scatter diagram and diagram of loading were re-ceived and the differences of metabolites were found out by the comparison . The results showed that compared with the blank control group, contents of creatinine, guanidinoacetic acid, trimethylamine, taurine, allantoin metabolites in the model group had elevated. And the contents of succinic acid, 2-OG, lactic acid, glycine, methyl nicotine metabolite had decreased. After medication, contents of creatinine, trimethylamine, allantoin, taurine of SQLD group were still higher than the blank control group. However, the contents were reduced compared with the model group. The content of lactic acid was lower than the blank control group, but higher than the model group. There was no statistical significance on changes of guanidinoacetic acid, 2-OG, N-nornicotine. It was concluded that substances found were mainly related to energy metabolism, inflammation and immune resistance, which was especially related to energy metabolism change obviously.