It was once a rite of passage for kids to have their tonsils taken out. Now, it's relatively rare. What's changed?

Years ago, doctors saw only the problems swollen tonsils can cause, like sinus or ear infections, and sometimes difficulty breathing. They reasoned, if it's our tonsils that ail us, take 'em out! However, now we know tonsils are lymphatic tissues with important immune functions, filtering out bacteria, producing antibodies and helping form white blood cells.

Strategically located in the throat and nasal passages, tonsils protect our respiratory and digestive systems from infection. If they're supposed to prevent infection, why do tonsils become swollen or infected? Location, location, it's all in the location, and structure, of our six tonsils.

If you open your mouth wide in the mirror and look at the arch in the back of your throat, you'll see small creases on either side. These creases extend back into two of the tonsils, making it easy for food or bacteria to enter and cause swelling and inflammation. At the back of the nasal passages, there's another pair of tonsils with similar creases, but these don't swell as often-maybe because we don't eat through our noses! The last pair of tonsils, in the base of the tongue, has glands that drain the creases well, so they rarely swell.

Because kids' tonsils are relatively larger than adults', kids still occasionally need them removed to prevent problems with infection or breathing. Other once-misunderstood lymphatic tissues, including the appendix, can take over the tonsils' work. However, in most cases, we need our tonsils right where they are, keeping us healthy.