Obstructive lung disease includes asthma and chronic obstructive pulmonary disease (COPD). Exacerbation of asthma or COPD can result in significant morbidity and mortality, and emergency department (ED) care is often required. ED evaluation should assess risk factors for severe exacerbation and the patient’s hemodynamic and respiratory status. Assessments including chest radiograph, point-of-care ultrasound, capnography, and electrocardiogram can assist. First-line treatments for acute exacerbation include bronchodilators and corticosteroids. Noninvasive ventilation, magnesium, ketamine, and epinephrine should be considered in those with severe exacerbation. Mechanical ventilation is challenging and should use an obstructive lung strategy with permissive hypercapnia.