Oxymetazoline
"I never knew of this product until about 10 years ago when I had the worst sinus infection of my life.  As was typical, the medication given by my doctor did nothing for the congestion and pressure and only made me tired and thirsty.  My wife came home with Afrin and with just one squirt in each nostril I had almost instant and dramatic improvement.  Since then, my doctors routinely tell me how bad this product is for me despite the fact that I have tried everything they have offered without improvement.  Now being on CPAP for sleep apnea Afrin is a must if I want to breath through my nostrils. "