- Neonatal asphyxia
- Nasopharyngitis
- Mycoplasma pneumonia
- Middle East Respiratory Syndrome (MERS)
- Malignant pleural mesothelioma
- Lysinuric protein intolerance
- Lymphangioleiomyomatosis (LAM)
- Lung injury
- Lung adenocarcinoma
- Lung abscess
- Legionella pneumonia
- Laryngitis
- Large cell carcinoma of the lung
- Interstitial lung disease
- Inhalation injury
- Influenza A