Leukotrienes are chemical compounds produced by the immune system that play a crucial role in inflammatory responses. They are derived from fatty acids and are involved in various processes, including bronchoconstriction, increased vascular permeability, and attracting immune cells to sites of inflammation. These compounds are particularly significant in conditions like asthma and allergies, where they can contribute to symptoms such as airway constriction and swelling. Medications that block leukotriene receptors, known as leukotriene receptor antagonists, are often used to help manage these conditions by reducing inflammation and improving breathing.