There is no prescription for cough expectorant, because there is no scientific basis for the prescription, it is not reliable. If you want to stop coughing and expectoration, you must take medication as prescribed by your doctor. Symptoms of cough and phlegm may be due to acute respiratory infections, such as acute bronchitis and pneumonia, or chronic airway diseases, including chronic bronchitis, bronchodilatation, chronic obstructive pulmonary disease, asthma, and so on. For cough and phlegm caused by the above mentioned etiologies, one should seek timely medical attention and should not believe in prescriptions, which do not have any scientific basis. When there is an unexplained cough, it is recommended to use medication under the guidance of a doctor, not blindly self-medication to avoid adverse effects.