You're sitting in the doctor's office, feeling crummy and hardly able to swallow. You watch and listen as the doctor grabs her prescription pad and says to your parent, "The test came back, and he's got strep throat. I've seen a lot of kids with it this week. Give him this medicine, make sure he finishes all of it, and he should be well enough to go back to school soon." So you go home and start taking your medicine. Sure enough, you quickly get better.

But what was in the medicine? How did it work to make you better? And how did the doctor know to give you that medicine instead of one of thousands of others? Medicines aren't really a mystery - keep reading and you'll learn more.

A Rainbow of Medicine
One medicine might be a pink liquid, another medicine might come in a special mist, another might be a blue pill, and still another might come out of a yellow tube. But they're all used for the same purpose - to make you feel better when you are sick. Some medicines are made from substances found in nature, like plants or animals. Others are made by scientists in laboratories. Most medicines today are made in laboratories and based on substances found in nature.

After a medicine is created, it is tested over and over in many different ways. This allows scientists to make sure the medicine is safe for people to take and that it can fight or prevent a specific illness. A lot of new medicines actually are new versions of old medicines that have been improved to help people feel better quicker.

Sometimes a part of the body can't make enough of a certain substance, and this can make a person sick. When someone has insulin-dependent diabetes (say: dy-uh-bee-teez), the pancreas (a body organ that is part of the digestive system) can't make enough of an important chemical called insulin, which the body needs to stay healthy. If your body makes too much of a certain chemical, that can make you sick, too. Luckily, medicines can replace what's missing (like insulin) or they can block production of a chemical when the body is making too much of it.

Most of the time when kids get sick, the illness comes from germs that get into the body. The body's immune system works to fight off these invaders, but the germs and the body's natural germ-fighting chemicals can make a person feel ill. In many cases, the right kind of medicine can help kill the germs and help the person feel better.