Mucinex Sinus-Max severe congestion relief caplets fight mucus, sinus pressure, and headache, so your worst symptoms don't get the best of you. Mucinex Sinus-Max severe congestion relief has a triple-action formula that contains three maximum-strength medicines. Acetaminophen relieves pain and headaches, guaifenesin works as an expectorant and thins and loosens mucus, and phenylephrine HCl works as a nasal decongestant and reduces swelling in the nose that causes sinus pressure. HSA/FSA EligibleFights mucus, sinus pressure, and headachesTriple-action formula that contains three maximum strength medicines