Anaphylactic shock in man is a catastrophic and often fatal reaction to a multitude of foreign substances, characteristically after previous exposure to proteins, polysaccharides, drugs, and chemicals to which the patient has been sensitized. Fortunately fatal anaphylactic reactions are surprisingly uncommon when viewed in relationship to the formidable incidence of allergic reactions, variously estimated as between 10% and 20% in both the American and English populations,1,2 but the reported incidence of fatal reactions is increasing. In a review of cases reported in the American literature between 1894 and 1924, Lamson cited a total of 55 instances of sudden death following injection of foreign substances, primarily foreign proteins.3 A more comprehensive inventory of cases, published in 1957, included a survey of hospitals, and accounted for 29% of the hospital beds in the United States. In a period of approximately 3½ years, this survey documented 809 acute reactions simulating anaphylaxis