Gentodenz can be used in the fractionation of nucleic acids, proteins, polysaccharides and nycleoproteins. Moreover most types of subcellular organelles can be successfully isolated on gradients of Gentodenz under either isotonic or mildly hypertonic conditions. Gentodenz has a low osmolality, and is non-toxic, thus making it an ideal medium for the separation of intact living cells. The low viscosi-ty of Gentodenz in parallel with it's non-ionic characteristics has pro- ved Gentodenz to be useful in the isolation and purification of viruses and bacteria.