[Protective function of the skin].

This paper reviews published data concerning the protective function of skin and discusses factors that may affect its bactericidal capability, including space flight factors that are known to reduce its protective effect. Various concepts of the mechanisms of the bactericidal function are discussed. It is shown that in an enclosed environment the species composition of the resident autoflora and pH value of the skin of an essentially healthy man may change. The qualitative composition of the water-oil film as a source of nutrition and a skin microflora environment is discussed. Its effect on the autoflora composition and localization in various skin areas and, consequently, on the bactericidal capability of different skin areas is described. The skin bactericidal function results from an interaction of various factors that should be taken into consideration when developing flight-oriented hygienic requirements because space flight induces changes in the skin status.