The presence of yellow sputum is a sign of inflammation and is an inflammatory reaction caused by a bacterial infection. Bacterial infections cause inflammation in the upper or lower respiratory tract, such as the throat, trachea, bronchi, and alveoli, and inflammatory exudates appear in these locations. Also, neutrophils in the body gather at the inflammatory sites and engulf foreign bacteria, and subsequently neutrophils undergo lysis and mix with inflammatory exudates to form yellow sputum. The most important treatment measure for inflammation is anti-inflammatory treatment, and if the yellow sputum is a bacterial infection, antibiotics are needed for treatment. For upper respiratory tract infections, oral amoxicillin, cefradine, and cefadroxil are recommended for treatment. If the yellow sputum is caused by bronchitis or pneumonia, intravenous antibiotics are needed for treatment, as well as medication for purulent sputum, such as pulmonary cough combination.