Purpose: Understanding the distribution and interaction of the Traditional Chinese Medicines (TCMs) is an integral source of herbal drug discovery. An optimized radio-labeled method was explored that could conduct in situ biodistribution studies in animals. We evaluated the feasibility of the method and applied glycyrrhetinic acid and platycodon (PG) polysaccharides as models. Procedures: [18F]-GA is a novel radiotracer which was performed positron emission tomography (PET) studies to assay the biodistribution of GA in mice. In addition, PG polysaccharide was used to intervene the biodistribution and dosimetry of GA. Scanning data were analyzed with professional software. Results: Record the time-activity curves for all organs then use the normalization method to calculate the area under the curve as a dosimetry for each organ. Moreover, the addition of PG polysaccharides can significantly improve the dosimetry of GA in the lungs, and its effect was related to the administration time. Conclusion: MicroPET imaging opens up a new avenue for the application of drug interactions between the TCMs.