Due to their good physicochemical properties, high biocompatibility and low toxicity, polysaccharides have been widely used as biomaterials in the fields of medicine and biology. However, in vivo investigations of their pharmacokinetics are significantly restricted by the difficulty in detection of polysaccharides. To date, polysaccharide labeling has become one of the most promising approaches for tracking polysaccharides in vivo. Here, we review fluorescent and radioisotopic labeling methods for polysaccharides and their applications in tracking polysaccharides in vivo , and compare the advantages and disadvantages of different labeling methods. The potential factors affecting the pharmacokinetics of polysaccharides in vivo were summarized, including the monosaccharide composition, charge, molecular weight and dosage of polysaccharides, as well as the physiological state of the organism. This review also prospects the applications of polysaccharides in medicine based on the reported pharmacokinetic characteristics in vivo. • Polysaccharides fluorescent and radioisotopic labeling strategies and principles • Advantages and disadvantages of polysaccharides pharmacokinetics studies via fluorescent and radioisotopic labeling • Potential factors affecting the pharmacokinetics of polysaccharides in vivo • Application based on the pharmacokinetic characteristics of polysaccharides in vivo [ABSTRACT FROM AUTHOR]