Amburana cearensis A. C. Smith, Fagaceae, is a medicinal plant commonly known as 'cumaru' and used in Northeast Brazil for the treatment of respiratory tract diseases. In the present work, we investigated the anti-inflammatory and smooth muscle relaxant activities of the hydroalcoholic extract (HAE), coumarin (Coum) and fl avonoid fraction (FF) isolated from the trunk barks of Amburana cearensis A. C. Smith. It was shown that HAE (200 and 400 mg/kg), Coum (20 and 40 mg/kg) and FF (40 mg/kg), administered orally, significantly inhibited both leukocyte and neutrophil migrations, in the carrageenan or N-formyl-methyl-leucyl-phenylalanine (fMLP)-induced migration in rat peritoneal cavity. The increase in cutaneous vascular permeability induced by serotonin in rats was significantly blocked by HAE (150 mg/kg, i.p.), Coum (5 mg/kg, i.p.) and FF (20 mg/kg, i.p.). However, only HAE blocked the histamine effect on Evans blue extravasation. In the guinea-pig trachea precontracted with carbachol (0.3 microM), histamine (0.1 microM) or KCl (0.1 M), the HAE, Coum and FF evoked a concentration-dependent relaxation in the presence of the three agonists. HAE (100-800 microg/ml) and Coum (4-32 microg/ml) also caused significant relaxation of the rat vas deferens previously contracted with adrenaline, acetylcholine or barium chloride. In addition, HAE, Coum and FF inhibited the histamine and serotonin-induced increase of cutaneous vascular permeability in rats.