Drugs composed of polysaccharides obtained from lipopolysaccharides extracted from bacteria

This invention concerns a protection and control agent against irradiation in living beings, composed of polysaccharides, called PS, obtained from lipopolysaccharides (LPS), which in turn are extracted from Gram-negative bacteria after separation of the major part and preferably all the initial lipid content of these LPS's. The molecular weight of the PS ingredients, once purified, is between 8,000 and 35,000 and mainly around 10,000. They contain: around 50 to 70% carbon hydrates by weight; around 1 to 8% hexoamines by weight; around 1 to 5% amino-compounds, among which 1 to 2% amino-acids by weight less than 1% and preferably no fatty acids or lipids and their phosphorus content is around 0.2 to 0.5% by weight