Major Mucus & Sinus Relief Tablets | Guaifenesin 400mg/Phenylephrine HCL 10mg | 60 Ct Mucus relief Guaifenesin is an expectorant that helps loosen and thin mucus in your throat so you can breathe easier through your nose and mouth while expelling mucus and phlegm. Avoid foul tasting cough syrups and liquids that need to be taken every couple of hours for lasting effects. Combat chest congestion, mucus and bronchial secretions caused by the common cold and flu. Does NOT contain Pseudoephedrine. Avoid foul tasting cough syrups and liquids and breathe easier with Major's Mucus & Sinus Relief Tablets. Contains Guaifenesin and Phenylephrine HCL that help combat chest congestion, mucus, and bronchial secretions caused by the common cold and flu.