Leukotrienes play an important role in the pathogenesis of asthma, a chronic inflammatory disease. They are potent bronchoconstrictors and chemoattractants; furthermore, they increase vascular permeability and mucus secretion. Early treatment of bronchial inflammation has become an essential element of the therapeutic approach of asthma and relies mainly on inhaled corticosteroids. However, known adverse effects of inhaled corticosteroids raise important long-term questions on their local and systemic tolerance. These safety aspects have encouraged the development of other anti-inflammatory drugs. Antileukotrienes (specific antagonist of receptors and inhibitors of 5-lipoxygenase) display a beta 2-agonist additive effect, confer an effective protection in bronchial provocations, improve both clinical and functional asthma scores and also allow a decreasing in short-acting beta 2-agonist use. They are intended for patients suffering from persistent mild-to-moderate asthma. However, further studies are still required to determine both their long-term efficacity and tolerance, to define their place in the strategy of asthma management and finally to clarify their application in other allergic diseases.