Mucinex Sinus-Max Severe Congestion Relief Liquid contains acetaminophen pain reliever guaifenesin expectorant and phenylephrine HCl nasal decongestant. Mucinex Severe Congestion Relief Medicine helps relieve symptoms such as sinus congestion headaches and thins and loosens mucus. This medicine temporarily relieves: nasal congestion headache minor aches and pains sinus congestion and pressure. It temporarily promotes nasal and/or sinus drainage. Mucinex Sinus-Max Severe Congestion Relief helps loosen phlegm (mucus) and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive.