Why You Probably Don't Need Antibiotics for a Cold or the Flu

Antibiotics are incredible, effective drugs. You may start to feel better soon after you begin taking one for a bacterial infection. Having experienced those results, you may think of seeing your healthcare provider to request an antibiotic whenever you feel sick. Going to see your healthcare provider when you don't feel well is always a good idea, but the chances are that you don't need an antibiotic. In fact, taking antibiotics when they are not indicated can do more harm than good.


What Antibiotics Do

Antibiotics can kill bacteria or slow their ability to multiply.

The first antibiotics discovered were natural products of molds and other organisms. Infections that once killed untold millions could finally be cured and came to be considered minor and treatable. Newer, laboratory-synthesized drugs have joined the ranks of antibiotics effective against a wide variety of bacteria.

Why Antibiotics Don't Work For All Illnesses

Bacteria are microscopic organisms found throughout nature. They can live inside or outside the human body; some—such as the bacteria in your digestive system— are beneficial and necessary for good health. Others, however, are pathogenic, meaning they cause infection and illness.

Certain bacteria are responsible for a variety of human respiratory infections, including some sinus and ear infections, certain kinds of pneumonia, and strep throat. These can be targeted and effectively neutralized by antibiotic drugs.

The common cold, influenza, and other viruses, on the other hand, are not caused by bacteria. When you get a viral infection, the virus invade your body's cells, using their machinery to help make more and more viruses.

Antibiotics do not kill viruses, so they won't shorten a viral illness. Instead, there are some antiviral medications that can be used against specific viruses, such as influenza or HIV.

Why Can't I Take an Antibiotic Just in Case?

Aside from the fact that an antibiotic won't work unless your illness is bacterial in nature, there are significant problems with the unnecessary use of antibiotics.

For one, it upsets your body's balance of beneficial bacteria, which may lead to antibiotic-associated diarrhea and the development of an allergic reaction to the drug.

It also leads births antibiotic-resistant bacterial strains. When bacteria are exposed to an antibiotic, many are killed, but some that are resistant to the drug's effects usually remain. In other words, the antibiotic kills off the weakest bacteria while the stronger resistant bacteria continue multiplying. With this, the bacteria develop the ability to beat the drugs designed to kill them off.

The eventual result can be superbugs—bacteria that become resistant to several types of antibiotics. These are very hard to kill and may only succumb to extremely powerful versions of these drugs. In fact, the Centers for Disease Control and Prevention (CDC) estimates that at least 2.8 million people are infected by these superbugs every year in the U.S., with at least 35,000 people dying from them.

The powerful antibiotics needed for killing superbugs are much more costly and pose a greater risk of significant adverse effects that may require hospitalization. Some superbugs go on to cause devastating and even fatal infections that are incurable with current antibiotics.

Examples of antibiotic-resistant superbugs include:

Is My Infection Bacterial or Viral?

This distinction can be tricky, which is why it's worth a visit to your healthcare provider to be evaluated. People with underlying lung problems (such as asthma or chronic obstructive pulmonary disease) or other chronic illnesses may be more prone to bacterial infections and should seek a professional opinion sooner rather than later.

Generally speaking, however, there are some ways bacterial and viral infections can be differentiated.

Viral Illnesses
  • Most produce a wide variety of symptoms, such as a sore throat, sniffles, cough, and body aches

  • Usually abate after a week

Bacterial Illnesses
  • Often cause a more focused area of discomfort, such as a severely painful ear or an extremely sore throat

  • Symptoms usually last for longer than 10 to 14 days

Viral illness that last more than 10 days or that grow suddenly worse after five to seven days may be signs that you have developed a secondary bacterial infection. While you did not require antibiotics for the initial viral infection, you will need them now.

Some of the signs (like thick, green mucus) used to be thought of as being suggestive of the presence of a bacterial infection, but this is no longer believed to be accurate.

Proper Antibiotic Use

Don't insist on an antibiotic; ask your healthcare provider why you do or do not need one. If you do, follow your healthcare provider's instructions.

Don't stop an antibiotic just because you begin to feel better. Not taking the entire prescription may allow resistant bacteria to thrive and not be completely killed off.

Also keep in mind that prescription medications are never meant to be shared. Don't ever take someone else's antibiotic, and don't give yours to anyone else either.

If it turns out that you don't have a bacteria-related illness, resist the urge to ask for these medications. Instead, treat the symptoms you have so you can rest a bit more comfortably until your infection passes.

A Word From Verywell

Using antibiotics as and when directed is essential to these drugs working when you need them most. But to help avoid needing them altogether, make sure you get get a yearly flu vaccination. Though the flu is viral, vaccination can help you reduce the risk of secondary bacterial infections that may follow, which include sinus infection, ear infection, and bacterial pneumonia.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. About antibiotic resistance.

  2. Centers for Disease Control and Prevention. Viruses or bacteria: What's got you sick?

  3. Centers for Disease Control and Prevention. Antibiotic/Antimicrobial Resistance (AR/AMR). Protect yourself and your family.

Additional Reading

By Naveed Saleh, MD, MS
Naveed Saleh, MD, MS, is a medical writer and editor covering new treatments and trending health news.