Cough medicine in bottles, next to a stethoscope and pills in their packaging. This cough medicine is also called linctus, a general term that means cough. Cough medicines are generally designed to either suppress coughs (a cough suppressant) or to increase the effectiveness of a cough's expulsion of phlegm from the lungs (a cough expectorant). A stethoscope is used to listen to sounds within the body. The round component seen here contains a diaphragm that transmits the sound to earpieces (not seen). A stethoscope is usually used to diagnose disorders of the heart and lungs. A cough is a sign of a lung disorder.