BY MICHAEL ROIZEN, M.D., AND MEHMET OZ, M.D.

When it comes to helping to keep the flu and other illnesses away from you, you know the four most important things you can do:

Wash your hands if you shake someone else's

Wash your hands before and after you touch anything

Wash your hands before and after you eat

Wash your hands (did we say that?)

Your hands, however, aren't the only things that need washing. It's important to keep highly touched surfaces clean, too. Especially one in particular: Your phone (iPhone and BlackBerry addicts, that especially means you!). The device that you use to reach out and touch someone may be touching you back with dirt, germs and other baddies. In a study of household surfaces in kitchens and bathrooms, researchers discovered that phone handsets and mouthpieces were two of the most contaminated even more so than baby gear (including baby changing mats!).

Here's why you need to rub down your phone with disinfecting wipes: Viruses can survive on some surfaces for hours, or even days, depending on the room's humidity and temperature. And once you touch a contaminated surface, it's maddeningly likely that the virus will be transferred to your nose or mouth and bingo, the bug's in your body. So clean your phone, and don't forget to wash your hands afterward.

The YOU Docs Mike Roizen and Mehmet Oz are authors of "YOU: Being Beautiful The Owner's Manual to Inner and Outer Beauty." To submit questions and find ways to grow younger and healthier, go to www.RealAge.com, the docs' online home.