Abstract: For the first time individual (free from impurities of penta- and hexa-acetylated derivatives) di-, tri- and tetra-acetylated S-LPS of endotoxic bacteria and combinations thereof were obtained and their immunobiological, physical-chemical and chemical-pharmaceutical properties were studied. For the first time the principal possibility of their clinical application was directly demonstrated as vaccines and pharmaceutical compositions containing the modified S-LPS individual as monocomponent or combinations thereof as two and three component active substance, respectively. The modified S-LPS and combinations thereof have high safety profile and provide low pyrogenicity and high immunogenicity. Developed on their basis vaccines and pharmaceutical compositions demonstrate anti-shock activity, high efficiency and specificity, broad-spectrum action and also good chemical-pharmaceutical parameters.