This is a combonation of Guaifenesin (an expectorant- it helps to thin and loosen mucus so you can expel it (through coughing or nose blowing, depending on where the mucus is) and the other ingredient, the PSE is pseudoephedrine hydrocholoride, the generic name for Sudafed (a decongestant). The medicine will not help you get well (unlike an antibiotic) but it will make you more comfortable by lessening the symptoms. I get a lot of sinus infections and I am figuring you like have sinus pain/pressure and stuffiness. Hope you feel better. Like the info. that comes with the medicine says- drink plenty of water. If you don't, you could feel worse. You need fluids to help you get the mucus thinned and out and you don't want the PSE part to dry out your nose too much- that can be very uncomfortable. I hope I wasn't too detailed here. I tend to be long-winded... sorry...