The BEST product to help prevent sinus infections, and I have tried them ALL. My Naturopath started me on this in 2003 and I went from frequent/chronic and serious infections about every 6-8 weeks that would have me out of work sick and throwing up to only three in 14 years (only when I am not staying on top of things). My physician had wanted me to consult for surgery when I just kept having infections, my allergist said I would "just always have them" ( what kind of answer is that?!...) I also had constant post nasal drip and constant throat clearing. I was taking over 120mg of sudafed daily! Crazy! And still had horrible issues...I saw a Naturopath and he knew exactly what I needed. I take this daily and as I said it has made an immeasureable difference. The biggest thing to remember is that it is not a drug, it is an herbal supplement, it must be taken as such - daily. Follow the dosage, it decreases after the beginning dosage to a "maintenance" dose of sorts. I have gone off a few times and have to get back on at the higher dose to start back up. Totally worth it!