It's a common misconception that if you're feeling sick, you should take antibiotics. They can help in some cases, but taking them when it's not necessary can lead to serious consequences.

Bacteria are small organisms that usually cannot be seen with the naked eye. Some can cause infections, though most don't pose a danger to humans. Good bacteria are beneficial and used in food processing, such as yogurt or wine fermentation. The harmful ones lead to problems like urinary tract infections and Strep throat.

Viruses are smaller than bacteria. Some can cause harm. Examples include the common cold, influenza, and viral hepatitis (inflammation of the liver).

Read: 5 Myths About Antibiotics

You should only take antibiotics to treat infections caused by bacteria.

"Antibiotics are not effective against viruses, so they don't treat illnesses like the common cold or flu," says Hai Tran, PharmD, associate director of drug use policy at Cedars-Sinai.

Read: Viruses, Bacteria and Fungi: What's the Difference?

Bacteria find ways to resist being killed. They're survivors. Bacteria can build up resistance if antibiotics are overused. When resistance develops, antibiotics may not work as well, or may stop working completely.

"Some bacteria have become so resistant that they can't be treated with most antibiotics," says Tran. "These are sometimes called superbugs, and they can be very difficult, if not impossible, to treat."

In Discoveries: Pro Solutions to Antibiotics Problems

Avoid getting infections by taking care of your body and practicing good hygiene, such as regular handwashing. Also, make sure to only take antibiotics when necessary and prescribed. Taking antibiotics when not needed can lead to antibiotic-resistant infections in the future.

Do not take medication not prescribed to you. If a medication is prescribed to you, take it as directed. Follow the instructions on the label and as explained by your pharmacist. Ask questions if needed, and finish the medication unless otherwise instructed.

If you're feeling under the weather, make an appointment with your primary care physician or visit urgent care.