[Superweak effects of chemical compounds and physical factors on biological systems].

The results of extensive investigations of the responses of living systems to superweak influences are summarized. The results of the effect of ultralow concentrations of various biologically active substances and ultraweak physical fields (primarily electromagnetic) on biological systems of different level of organization, from molecular to population, were considered. Several single-type regularities peculiar to all systems were revealed: polymodal dose dependences, the efficiency of influences at doses below the background level and its dependence on the state of the system, the modification of the sensitivity of a system to subsequent influences, etc. Several hypotheses of the mechanisms of superweak influences and the role of water as a universal intermediate in these processes are presented. Possible consequences of the phenomenon and its applications in practice are discussed.