Dextran is a polymer of anhydroglucose. It is composed of approximately 95% alpha-D-(166) linkages. The remaining (163) linkages account for the branching of dextran.

Dextran sulfate is routinely used for the selective precipitation of lipoproteins, probe hybridization membrane-immobilized DNA, the release of DNA from DNA-histone complexes, and the inhibition of RNA binding to ribosomes ; Dextran sulfate is used as a diluent in in situ hybridization experiments to increase hybridization of probes to target sequences in tissues.

Treatment with dextran sulfate sodium triggers development of colitis in mice and rats by binding to medium-chain-length fatty acids present in the colon and inducing inflammation.