Transitory pulmonary infiltrations associated with eosinophilia of the peripheral blood has been described as an allergic reaction ocurring principally in persons with parasitic disease such as amebiasis, trichinosis, ascariasis and cutaneous helminthiasis.1 This condition, usually referred to as Loeffler's syndrome, is somewhat variable in its course and severity, but is generally characterized by relatively mild clinical symptoms, which include fever, paroxysmal cough with sputum containing eosinophils, slight to moderate leukocytosis with eosinophilia and migratory pulmonary infiltrations evident roentgenographically.2 A plausible theory of the mechanism involved in Loeffler's syndrome is that the vascular system becomes hypersensitized to an extrinsic allergen and that the small blood vessels and capillaries of the lungs act as one of the shock structures. The damage to these vessels causes increased permeability of their walls, resulting in the pulmonary infiltrations.3 We have recently observed 2 patients with allergic reactions to penicillin in oil and