Our previous studies show that provinol, a polyphenolic compound, has anti-inflammatory activity during allergic inflammation. In the present study we investigated the effects of provinol and its combinations with clinically used antiasthmatics: budesonide or theophylline on airway defense mechanisms during experimental allergic asthma. Separate groups of guinea pigs were treated during the course of 21-day ovalbumin sensitization with provinol (20 mg/kg/day, p.o.), or budesonide (1 mM by inhalation), or theophylline (10 mg/kg/day, i.p.), and with a half-dose combination of provinol+budesonide or provinol+theophylline. Airways defense mechanisms: cough reflex and specific airway resistance (sRaw) were evaluated in vivo. Tracheal smooth muscle reactivity and mucociliary clearance were examined in vitro. The findings were that provinol caused significant decreases in sRaw and in tracheal smooth muscle contractility, a suppression of cough reflex, and positively modulated ciliary beat frequency. The bronchodilatory and antitussive effects of provinol were comparable with those of budesonide and theophylline. Provinol given as add-on treatment significantly potentiated the effects of budesonide or theophylline, although the doses of each were halved. We conclude that provinol not only has bronchodilatory and antitussive effects, but also potentiates similar effects exerted by budesonide and theophylline.