Cough suppressants are usually divided into peripheral cough suppressants and central cough suppressants. The so-called peripheral cough suppressants act on the sensitive nerves of the cough and can reduce the sensitivity of the cough. Other central cough suppressants, such as dextromethorphan and forcodine, belong to the central category, but they may have a certain inhibitory effect on the respiratory center and are usually not used in less severe cases. Phenylparaben is also very effective in relieving cough and is very effective for mild coughs with very low side effects, so it is fine to use it for mild and moderate coughs.