Asthma is a chronic inflammatory disorder that affects the respiratory tract. It involves airflow obstruction, bronchial hyperresponsiveness and some sort of inflammation. Airflow obstruction can be caused by many different changes in the airway such as bronchoconstriction, airway edema, airway hyperresponsiveness, and airway remodeling. Bronchoconstriction is the main reason for airflow obstruction in asthma which results from a IgE-dependent release of mediators from mast cells, this can be stimulated by exercise, cold air, and irritants or allergens. New research has shown that the origins of asthma occur in the earlier stages in life. There are two major factors that can cause a person to develop asthma: particular genetics or environmental exposures that occur at a crucial time in a development of the immune system. In genetics asthma is characterized by a shift toward a Th2 cytokine-like disease, either as overexpression of Th2 or underexpression of Th1. Asthma is characterized by the infiltration of the airway T cells. Asthma is classically recognized as the typical Th2 disease, with increased IgE levels and eosinophilic inflammation in the airway. Emerging Th2 cytokines modulates the airway inflammation, which induces airway remodeling. This airways remodeling narrows the airway causing the person to have difficulty breathing.