Mucinex D is an expectorant and nasal decongestant. Mucinex D helps loosen phlegm and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive. Mucinex D relieves nasal congestion, temporarily restoring freer breathing through the nose. Mucinex D promotes nasal and sinus drainage, and relieves sinus congestion and pressure. Each tablet of Mucinex D contains 1200 mg of guaifenesin and 120 mg of pseudoephedrine. Take one tablet every 12 hours to relieve symptoms. There are 24 extended-release bi-layer tablets.