Beta 2-receptor agonists have recently been reported to be effective on allergen-induced late-phase reaction (LPR) in addition to their inhibitory effect on immediate-phase reaction, although the precise mechanism is not fully understood. In this study, we tested the effect of a selective beta 2-agonist, procaterol, on human basophil migration, which may be an important characteristic of LPR. Procaterol inhibited IL-8- and C5a-induced basophil migration in a dose-dependent fashion; 10(-7) M of procaterol reduced 30% of migration induced by both factors. The action of procaterol was rapid since the inhibition of migration was detected without preincubation and was not via the toxic effect on basophils as assessed by trypan blue test. The results of this study extend the repertoire of anti-inflammatory actions of beta 2-agonists.