Using an antifungal medicine that's meant to cure athlete's foot won't help the measles because it is caused by a virus. An antiviral drug for chickenpox won't help a finger cut that's infected by bacteria. So why would antibiotics do any good for a cold that's caused by a virus?

Antibiotics have been used so often that they aren't as good at fighting bacteria as they used to be. To make sure antibiotics continue to be helpful when needed, it's important not to misuse them.

If you think you need medicine to fight an illness, make sure you get the right kind of drug. Don't assume that you need an antibiotic. Then make sure you take the medicine exactly the way your doctor says to.

Antiviral drugs are used for infections caused by viruses.
Antifungal drugs are used for infections caused by fungi.
Antibiotic drugs are used for infections caused by bacteria.