Analysis of the temperature dependences of the denaturation enthalpy of three domains of albumin molecule showed significant distinctions in the destabilizing effect of ethanol on certain domains of the nondefatted and defatted albumin molecules. A linear relationships were found among the parameters of proteins and membranes stability and bulk dielectric constants of the solvents. It has been suggested that the dielectric characteristics of the medium play a significant role in the maintaining of the certain conformation of proteins and membranes.