Chlorpheniramine maleate (antihistamine), Phenylephrine hydrochloride (decongestant), and Dextromethorphan hydrobromide (cough suppressant). Chlorpheniramine maleate works by blocking the action of histamine, a substance responsible for causing allergic reactions. Phenylephrine hydrochloride helps in shrinking the blood vessels located in the nasal passage, thereby reducing the stuffy nose. Dextromethorphan hydrobromide works by blocking the transmission of nerve signals from the cough center in the brain to the muscles that produce cough. Together, it helps to provide relief from dry cough.