On the basis of their experience in the intensive therapy unit, correlated with modern pharmacokinetic data, the authors discuss the adverse effects induced by polyvalent therapy in septic shock, and which may be listed in the group of iatrogenic pathointerference. To the biochemical and functional alterations of shock may be added the possible effects of antibioticotherapy, corticotherapy, plasma expanders, lipid emulsions, crystalloid solutions, alkaline correcting solutions, osmotic diuretics, oxygenotherapy, vasoactive drugs, heparin and epsilon-amino-caproic acid. The possible summation of these effects should be indicated in the rules for observance by the medical staff of intensive therapy units.