Tracheitis and bronchitis are one of the most common diseases in all ages. Acute tracheobronchitis is common in children as well as in old patients, less common in the Middle Ages. The causes are in most instances infections. In children viral infections dominate the infectious spectrum. Bronchial asthma is a chronic inflammatory disease of the conducting airways, in which the epithelium and cells of the innate and adaptive immune system are involved. Asthma affects approximately 300 million people worldwide, and its incidence is increasing, especially in developed countries. The leading symptom is hyperreactivity of the airway smooth muscle cells. Bronchiolitis most often is associated with either bronchitis such as in asthma, or it is associated with pneumonia, an example is organizing pneumonia. However, there are two reasons to discuss bronchiolitis separately: Bronchiolitis is the underlying pathology and clinically called small airway disease, and it does occur sometimes as an isolated disease confined only to bronchioles.