ABSTRACT
Polysaccharides are the important material basis of traditional Chinese medicine（TCM）， and have various pharmacological activities such as immunomodulation， antitumor and anti-aging. Due to the large molecular weight of TCM polysaccharides， their structural analysis and oral absorption mechanism are facing technical challenges， and the current research on their structure-activity relationships has made some breakthroughs， while the research on their oral absorption mechanisms is relatively slow. In-depth study of the oral absorption mechanism of TCM polysaccharides is not only crucial for the interpretation of their action pathways and efficacy in vivo， but also helpful for the interpretation of their pharmacological effects， rational clinical applications and the discovery of new targets. In recent years， the application of fluorescent labeling and isotopic labeling methods has provided new technical means for the oral absorption studies of polysaccharides， which has promoted the development of oral absorption studies of TCM polysaccharides. In this paper， we reviewed the oral absorption pathways and labeling techniques of TCM polysaccharides， and concluded that they can be absorbed orally through transmembrane， cellular bypass， and M-cell-mediated transport， of which transmembrane pathway is the main absorption pathway， and summarized the labeling reactions of four fluorescent labeling and isotopic labeling methods with TCM polysaccharides， which can provide references for evaluating the absorption pathways of TCM polysaccharides， screening active TCM polysaccharides， establishing pharmacodynamic models and comprehensively elucidating the mechanism of TCM polysaccharides.