A selective model to study the IgE-mediated anaphylactic bronchoconstriction (BC) in the guinea pig is needed, since human asthma involves mainly this class of antibody. However, most procedures presently available for passive homologous or active sensitization lead to responses which are mediated both by IgE and IgG antibodies. In this study, we developed an anaphylactic model in which guinea pigs are passively sensitized with mouse ascitic fluid containing dinitrophenol (DNP)-specific IgE antibodies. Challenge of sensitized animals with DNP coupled to bovine serum albumin evokes a bronchoconstrictor response that is maximal 5 h after sensitization. The resulting anaphylactic BC is not blocked by the H1 histamine antagonist mepyramine, by the peptido-leukotriene antagonist FLP 55712 nor by the platelet-activating factor antagonist BN 52021 alone. However, when the sensitized animals are pretreated with the three drugs in combination, significantly reduced BC was observed upon challenge with the antigen. This latter result indicates that IgE-dependent BC involves the participation of different mediators, a characteristic shared in common with allergic asthma in human.