It has been shown that in the complex use of polyene antibiotics with dimethyl sulfoxide, the biological activity of antibiotics sharply increases. Comparative physical and chemical characteristics of dimethyl sulfoxide and polyene antibiotics are presented. Effects of complex interaction of dimethyl sulfoxide and polyene antibiotics with bilayer lipid membranes are considered. By the method of bilayer lipid membranes parameters of biological activity of polyene antibiotics are determined. It is shown that amphotericin B and levorin were the most effective among all polyene antibiotics is studied. The results of the dependence of the ionic conductivity of lipid membranes on the concentration of amphotericin B and levorin and on the concentration of cholesterol in membranes are presented. On the basis of polyene antibiotics, effective membrane-active preparation against viral and fungal diseases of plants have been developed.