Compared to other drugs taken with water, the viscous cough syrup does not seem to be very “close” to water. This is because drinking a lot of water immediately after taking the medicine will affect the absorption of the cough syrup in the gastrointestinal tract and weaken its therapeutic effect. Therefore, patients who use syrup to stop coughing should not rush to drink water. Because of the bitter taste of cough syrup, most people drink water immediately after drinking the medicine to dilute the taste. Cough is caused by increased sputum secretions after a respiratory infection, which irritates the mucous membrane of the airways. However, cough syrup is used for the purpose of resolving phlegm and relieving cough through blood circulation, rather than acting directly on the respiratory tract. Therefore, after the syrup is drunk, it must enter the blood circulation from the gastrointestinal tract in order to suppress the cough center. If you drink water after drinking the syrup, the unpleasant taste of the medicine in your mouth is relieved, but it also dilutes the syrup in your stomach and intestines, slowing down the absorption of the medicine, reducing its concentration in the blood and weakening its effect. In addition, a few cough suppressants contain topical mucosal protective components, such as glycerin. This drug generally covers the surface of the inflamed pharyngeal mucosa, forming a protective film to reduce the mucosal inflammatory response and block irritation, thereby reducing the cough caused by the pharyngeal mucosa. If you drink water too early, it will also dilute the medicine and weaken the coughing effect. When taking cough syrup, it is also important to note that when multiple drugs are taken at the same time, the cough syrup should be taken last to avoid diluting the other drugs; cough syrup containing mucosal protective drug ingredients should not be taken with hot water. If the mouth of the cough syrup bottle is opened, it loses its airtight and sterile environment and is easily contaminated.