Acetylcysteine capsule is a mucolytic agent, the sulfhydryl group contained in its molecule can break the disulfide bond in the polypeptide chain of glycoprotein in sputum thus reducing the viscosity of sputum and facilitating sputum expulsion. Adverse reactions such as nausea, vomiting, rash and bronchospasm may occur during administration. This product is mainly used for thick sputum mucus excessive respiratory diseases, such as acute bronchitis, acute exacerbation of chronic bronchitis or bronchiectasis. It is contraindicated for those who are allergic to the product, and the drug is used with caution or contraindicated in patients with bronchial asthma. Patients with bronchial asthma should be closely monitored during the use of the drug, and if bronchospasm occurs the drug must be stopped immediately. If you need to use the drug, it is recommended to use it under the supervision of a doctor to avoid unauthorized use.