If you're feeling crummy, it's probably because nasty bacteria or some other germs have gotten into your body and made you
sick. Bacteria are so tiny that you can't see them with just your eyes, but there
are thousands, millions, even billions of them all over you, inside and out! This
might sound kind of gross, but lots of bacteria actually help our bodies. The good
bacteria are good for us, and the bad bacteria can make us sick. They may be to blame
for your next sore throat or ear infection!