Germs are everywhere - in the air and on everything. They just are too small to see with your eyes.

There are four kinds of germs. They come in many shapes and sizes. Bacteria and virus germs are the ones that usually make you sick.

Bacteria
If bad bacteria get into your blood, it will give off poisons. When enough poison is in your blood, you will get sick. You may get a headache, ear ache, stomach ache or a cavity in your tooth. Medicine helps kill the bacteria and makes you feel better.

Virus
Virus invades your cells. Virus causes colds, the flu, measles and many other diseases. There are no medicines to kill a virus. But, there are medicines that help protect you from getting viruses - they are called vaccines. Some viruses can live for a while on something like a doorknob, so wash your hands often!

Germs enter your body through a cut or scratch, through your nose, your eyes and your mouth. If germs get in your body, the white blood cells in your body fight the germs and try to kill them. But sometimes the germs are too tough. In a couple hours, they can multiply into a million germs!

How do doctors figure out what is making you sick? They look at samples of your blood, saliva or other fluids under a microscope. The doctor can tell which kind of germ you have and how it is making you sick.

If you are sick, it is best to eat healthy foods, drink lots of water and get lots of rest. These help your body fight the germs and help you feel better faster.

Check out our "Tips to Stay Healthy" page for more germ-fighting tips.