Leukotrienes are chemical compounds produced by the body that play a crucial role in the immune response. They are derived from fatty acids and are primarily involved in inflammation and allergic reactions. By promoting the contraction of smooth muscles and increasing blood vessel permeability, leukotrienes help to regulate processes such as bronchoconstriction in conditions like asthma. These compounds are synthesized by various cells, including mast cells and white blood cells. Due to their significant role in inflammatory diseases, medications that block leukotriene receptors, known as leukotriene receptor antagonists, are often used to treat conditions like asthma and allergic rhinitis.