Inflammation in the bronchi of the lungs. Microbes and foreign matter that have entered the airways cause inflammation of the bronchi and stimulate excess secretion of mucus. Symptoms include a productive cough and a sensation of chest congestion. Long-term repetitive injury, as from smoking, may lead to chronic bronchitis, in which severe, irreversible damage leaves the lungs open to infection and fibrosis. Smoking-related chronic bronchitis often occurs in association with emphysema (together called chronic obstructive pulmonary disease). Treatment includes drugs to dilate the bronchi and promote coughing, antibiotics, and lifestyle adaptations (e.g., quitting smoking).