Used as an antitussive (cough suppressant) in over-the-counter cold and cough medications. It works by reducing the activity of the cough reflex in the central nervous system. Commonly found in liquid and tablet formulations, often combined with other active ingredients like antihistamines, decongestants, or expectorants to treat multiple cold symptoms. Effective for temporary relief of dry, non-productive coughs. Not recommended for use in children under a certain age due to limited evidence of effectiveness and potential side effects.