Emphysema is a disease caused by destruction of cells in the lungs. There is no effective treatment for emphysema; care involves smoking cessation and drug therapy with bronchodilators, with home oxygen therapy used if the condition worsens.

Idiopathic pulmonary fibrosis is a disease in which collagen accumulates during the repair of damage to the alveoli, thickening the interstitium and causing fibrosis, so that the lungs cannot expand sufficiently. Other forms of interstitial pneumonia include idiopathic nonspecific interstitial pneumonia and cryptogenic organizing pneumonia. Interstitial pneumonia, including idiopathic pulmonary fibrosis, is registered as a designated intractable disease, and there is no established treatment. Drug therapy with steroids is commonly used for symptoms, but steroid side effects mean it is considered a limited treatment.