Exercise-related anaphylaxis is a novel form of physical allergy that is being recognized with increasing frequency in a society with a growing commitment to health through planned exercise. The clinical manifestations progress from pruritus, erythema, and urticaria to some combination of cutaneous angioedema, gastrointestinal and laryngeal symptoms and signs of angioedema, and vascular collapse. The finding of an elevated serum histamine level during experimentally-induced attenuated attacks indicates mast cell participation, as in a physical allergy, and the signs and symptoms are characteristic of a classic anaphylactic reaction to a foreign substance in an allergic human.