Ethnopharmacological relevance: Gualou-Xiebai-Banxia decoction (GXBD) was a classical traditional Chinese medicine formula for the treatment of coronary heart disease. However, the current study on the chemical and metabolite profiles of GXBD did not follow the ancient prescription and extraction method, which hindered the discovery of effective compounds and quality control. Materials and methods: In this study, we prepared GXBD by ancient prescription and extraction methods, and then analysed the chemical components and xenobiotics of GXBD in vivo using high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry and in-house software. Results: 49 chemical constituents were preliminarily identified, including 7 terpenoids, 6 flavonoids, 5 alkaloids, 17 organic acids, 8 steroids and steroidal saponins, 2 nucleosides and 4 other types of compounds, of which 10 constituents were confirmed unambiguously with authentic standards. Moreover, 129 metabolites were tentatively identified, including 83 metabolites in plasma, 39 metabolites in urine, 25 metabolites in bile and 9 metabolites in feces. Our study speculated that luteolin, adenosine, vanillic acid and curbitacin B might be possible effective components of GXBD for the treatment of coronary heart disease. Dehydration, deglycosylation, dehydrogenation, acetylation and taurine regulation were the main biotransformation reactions of GXBD. Conclusion: Our results provided an important basis for the discovery of effective compounds and quality control of GXBD. In addition, in-house software was an useful tool for identifcation of metabolites.