Shock due to an infection is peripheral vascular collapse with progressive hypotension due to a variety of Gram-positive and Gram-negative bacteria, Rickettsiae, and viruses. Infection by coliform bacteria has been the commonest cause of this type of vascular failure. The endotoxin of Gram-negative bacteria, which is a lipoprotein-carbohydrate complex, is liberated into the blood stream and "triggers off" the physiologic and metabolic alterations. Endotoxin shock has been applied to this form of vascular failure. The exotoxins of the Clostridia species and of Staphylococcus also produce a similar pattern. During the initial stages of shock due to infection the patients are alert and exhibit fever, chills, pallor, tachycardia, hyperpnea, and a moist skin. Progressive deterioration is associated with a decline in temperature, a cold clammy skin, and the appearance of oliguria or anuria. The initial basic physiologic disturbance is severe vasoconstriction, followed by or alternating with vasodilation, and the venous pooling