Based on results of 15-years complex study, the authors present toxicological and hygienic characteristics of terpene compounds (with mono- and bicyclic structure) and their compositions. The article deals with toxicodynamics and toxicokinetics of terpenoids, dependence of toxic properties on the chemical structure. The article also touches upon studies of biologic and specific (sensibilizing activity, embryotoxic and gonadotropic, membranotropic) effects of terpenoids. Some aspects concerning hygienic regulation of terpene compounds are also covered.