A hydrocortisone preparation containing methylparaben and propylparaben provoked bronchospasm and pruritus when given intravenously to an asthmatic patient, whereas another hydrocortisone preparation without paraben preservative did not. Direct and passive transfer (Prausnitz-Küstner) skin tests for immediate hypersensitivity to parabens were positive. Parabens, frequently employed as bacteriostatic agents, are capable of producing immunologically mediated, immmediate systemic hypersensitivity reactions.