[en] Inhalation of the platelet activating factor (PAF) produces symptoms of bronchial asthma, a disease in which PAF plays an important role. This lipid mediator released by many kinds of cells exerts its effects on blood cells and on cells of the bronchial wall both directly and indirectly. The crucial role played by PAF in the inflammatory cascades explains the current interest in specific PAF antagonists. These antagonists have both bronchodilator and anti-inflammatory properties and act simultaneously as beta-adrenoceptor agonists and corticosteroids. The first clinical trials of PAF antagonists in the treatment of resistant asthma have given results that are interesting but not superior to those obtained with the conventional anti-asthmatic drugs. The indications for PAF antagonists combined with other specific antagonists will soon be determined.