What the Mayo Clinic study discovered is that in a chronic sinus infection, the white
blood cells, called eosinophils, respond to an
infection by getting together
in the nasal
mucus and the sinus mucus, and they release a toxic protein, called major basic protein, into the mucus. It’s the poison inside the mucus, which we see as greenish or yellowish snot, which damages the nasal and sinus membranes.