DM Max consists of two ingredients, dextromethorphan and guaifenesin, used in preparations to relieve cough. Among them, dextromethorphan is a non-opioid drug used as an antitussive drug through inhibition of cough receptors in the central nervous system. At the same time, guaifenesin is a drug that clears respiratory secretions by diluting it to become easier to excrete.