Triterpene glycosides are widespread in plants belonging to various families and in animals of the class of echinoderms (Echinodermata). They are situated in essential organs and tissues. Dependent upon the physiological condition of the organism, their concentration and the velocity of their biosynthesis are variable within sufficiently wide limits. They are used by the organism in the struggle for life and in maintaining the biological equilibrium in antagonistic interactions of biological systems. As to plants, they are factors of immunity against fungal diseases. Like exogenous substances, triterpene glycosides are physiologically active against warm-blooded animals. They affect the metabolism, the functional status of the organs, and the organism as a whole. In biological systems, they are integrated with the metabolism and, like low-molecular regulators, they exhibit polyfunctional properties.