Summer colds are the worst. You don't want to stay in bed, because it's gorgeous out (not like that slushy day in February when you longed to curl up under the blankets). It's no wonder you are tempted to reach for that half bottle of antibiotics left over from last year's infected tooth.

Well, don't. Antibiotics do not treat viruses, the germs that cause colds (rhinovirus is the most common). Taking antibiotics for colds, coughs or flu is a waste of time and money.

Equally important: Next time you do have an infection requiring antibiotics, finish the entire bottle when it's prescribed—even if you feel better before taking the last dose. If you don't finish the entire course of pills, you may develop resistance to the antibiotic (meaning that when you do need it, it won't work).

And don't listen to your friend who swears that popping a few antibiotics at the first sign of a sore throat has worked for her: She probably had a cold virus that her body's immune system got under control by the next morning. The real cure in her case was most likely a good night's rest.