The effects of isoproterenol, salbutamol, theophylline, and forskolin on IgE antibody-mediated homologous passive cutaneous anaphylaxis (PCA) and on skin reactions caused by allergic mediators and mediator releasers were investigated in rats. Isoproterenol and salbutamol dose-dependently inhibited the PCA and skin reactions caused by histamine, serotonin, and leukotriene C4 (LTC4), elicited at the same time in the same rat. These agents also dose-dependently inhibited the skin reactions caused by platelet-activating factor (PAF), leukotriene D4 (LTD4), compound 48/80 (48/80), and calcium ionophore A23187 (A23187). Propranolol overcame the inhibitory effect of isoproterenol on PCA and skin reactions in a dose-dependent manner. Theophylline and forskolin showed similar effects as the beta-adrenergic stimulants. These results indicate that beta-adrenergic stimulants inhibit the increased vascular permeability caused by allergic mediators, and suggest that this activity of beta-adrenergic stimulants might play an important role in their antiallergic actions. Inhibition of increased vascular permeability might be mediated via beta-receptors and may be related to the increase in intracellular cyclic AMP levels.