The anaphylactic shock is a life-threatening reaction produced by the release of pharmacologically active substances (histamine, leukotriene...) by most cells and basophils. The release of these mediators may be immunologically mediated (anaphylactic reaction a typical immediate hypersensitivity reaction mediated by IgE) or not (anaphylactic reaction when not mediated by an antigen-antibody process). These mediators in turn specific end-organ responses in the cardio-vascular system, (vasodilatation, change in inotropy, increased capillary permeability), the respiratory system (bronchospasm upper airway oedema) and the skin (urticaria). Because of its etiology (mainly drugs, contrast media and colloids) the treatment of anaphylactic or anaphylactic reactions must be prophylactic. When it occurs, its cure is based upon adrenaline and fluid loading and eventually bronchodilators.