Nebulization for cough and sputum in adults generally uses phlegm-forming drugs, the most common of which is acetylcysteine nebulized inhalation solution, as this is the only type of phlegm-forming drug that can be used in nebulization at present. Acetylcysteine is the most commonly used phlegm medicine, mainly by breaking down the disulfide bonds on the glycoproteins in the phlegm, making the phlegm less viscous and thinner, thus facilitating the coughing up of phlegm, so acetylcysteine is often used in cases where the phlegm is thicker. Therefore, for adults with cough and phlegm, acetylcysteine can be used by nebulization to promote the discharge of phlegm, but in the end, treatment for adults with cough and phlegm should be directed at the cause. If the cough is caused by bacterial infection, antibiotics such as penicillin or cephalosporin should be given, and if the infection is fungal, antifungal treatment should be given, not just nebulized medication.