This article discusses the importance of the physical and chemical properties of the skin subjected to the action of the therapeutic physical factors. The author presents the data illustrating the influence of alterations in skin permeability on the penetration of medicinal substances into the organs and tissues of the body under conditions of application of various physico-pharmacological methods based on the use of chemical ingredients of peloid therapy and other balneotherapeutic technologies. The effectiveness of skin permeability is known to be of special importance in the context of physical therapy since it determines the action of its individual components. The influence of skin pH values as the parameters determining the peculiar features of percutaneous electrophoresis of cations and anions is demonstrated. It is shown that the reduction of electrical resistance of the skin barrier significantly improves the electrophoretic propagation of medicinal substances; therefore, such alteration determines, in many respects, the choice of the dosimetric parameters for electropuncture and electro acupuncture. Special attention is given to the discussion of the opportunities through which the variation of the skin optical properties could be applied to enhance the efficiency of phototherapy. The need to continue research on this problem topical for physiotherapy is emphasized.