Leukotriens are important as inflammatory mediators in allergic diseases, but still the role of leukotriens remains unclear and are required further studies. Over 80 years ago the slow-reacting substance of anaphylaxis (SRS-A) were first identified in the perfusates from isolated guinea pig lung subjected to an anaphylactic reaction in vitro. In 1979 the chemical structure and major arms of the 5 lipoxygenase pathway were defined. Metabolism of these primary leukotriens plays a central role in the determination of the biological activity of these molecule in vivo. The action of cytochrome P450 – dependent pathway is the predominant pathway of leukotriens metabolism in the liver. The process of beta-oxidation appears to be metabolic pathway for leukotriens when the cytochrome P450 pathway is not predominant. The most important role in allergic inflammation play leukotriens LTC4, LTD4 and LTE4, particularly in early allergic response. Leukotriens stimulate bronchoconstriction, airway remodeling. Elevated concentration of leukotriens (LTC4) was found as well in children with evidence of respiratory viruses. Three types of leukotriene receptors were identified BLT for LTB4; and CystLT1, CystLT2 for cysteinyl leukotriens (LTC4, LTD4, LTE4). Further study are necessary to determine the role of polymorphism of the gen coding CystLT1 receptor, which may have an impact on pharmacotherapy.