One of my favorite hobbies is gardening. I have a big perennial garden in my backyard that I've lovingly filled with a variety of plants -- from the tulips and mounds of white candytuft that bloom in the spring, to summer's irises and lilies, to the sedum that bloom in the fall. But one year I planted goldenrod. What was I thinking? Every time I even got near my garden I started sneezing rapidly like a machine gun shooting off rounds of bullets. Finally I donned a mask and pulled that noxious weed out, but it's made a valiant effort to return every year.

Have you ever wondered exactly what's happening when you sneeze? Sneezing is a protective reflex that clears your nasal passages of irritants like dust, pollutants, or pollens like the nasty ones from the goldenrod in my backyard. Nerve endings in the irritated nasal lining stimulate the brain stem which, in turn, stimulates muscles in the chest and throat to contract. Your eyes shut and your palate closes and the irritants are expelled through your nose and mouth. A sneeze can send 2,000 to 5,000 droplets chock-full of bacteria into the air at a pace of 70-100 miles per hour.