Do Antibiotics Weaken Your Immune System?

Written by

Jessica Guht

Jessica is a medical writer with an unquenched thirst to discover something new. She believes that medical content should be accessible to everyone and strives to write content that every single person can understand. When Jessica isn’t writing, she can usually be found reading a book with a dog cuddled in her lap. Jessica has a Masters of Engineering degree in Biomedical Engineering.

Medically reviewed by

Amy Dougherty, FNP-BC, AGAC

Amy is a Board Certified Family Health Nurse Practitioner (FNP) with over 15 years of experience working in Hospital Medicine, Urgent Care and Primary Care practices. Amy graduated Thomas Jefferson University with high distinction earning a Bachelor of Science in Nursing in 2008, a Master of Science in Nursing in 2010 and a Post Master's Certificate in Adult Gerontology Acute Care (AGAC) in 2014. She was recognized by the Elite American Nurses Association in 2013 for her dedication, achievements and leadership in the field Nursing. She served as a clinical preceptor for a number of Nurse Practitioner students and enjoys teaching the bright minds of future NPs.

Antibiotics are some of the most commonly prescribed medications and are taken to treat bacterial infections. This makes them imperative for your body’s health, but can they also weaken your immune system?

As medication that kills and destroys bacteria, antibiotics can also affect the good bacteria in your body. This good bacteria has many responsibilities, including its role in your immune system. As such, taking antibiotics can weaken your immune system and make it less effective. 

Continue reading to learn why we still take antibiotics, when they are not recommended, and how to boost your immune system while on antibiotics. 

Table of Contents

• What Are Antibiotics, and What Are They Used For?
• How Do Antibiotics Work?
• Do Antibiotics Weaken Your Immune System?
• How Can Antibiotics Weaken Your Immune System?
• How Can You Strengthen Your Immune System?
• Key Takeaways

What Are Antibiotics, and What Are They Used For?

Antibiotics are a type of medication used to treat bacterial infections. They can come as pills, liquid suspensions, ointments/creams, or IV infusions. Most antibiotics are only available as a prescription, but some topical creams can be purchased over the counter. 

Since antibiotics target bacteria, they cannot treat viral or fungal infections. 

Some infections that antibiotics may be used to treat include:

• urinary tract infections (UTIs)
• strep throat
• E. coli
• acne
• bronchitis
• sexually transmitted diseases (STDs)
• skin infections
• upper respiratory tract infection
• ear infection
• conjunctivitis (pink eye)
• eye infections
• gum disease
• meningitis

There are hundreds of different antibiotics, which vary based on their mechanism of action and, thus, the infections they treat.

How Do Antibiotics Work?

How antibiotics treat bacterial infections varies based on the type of antibiotic, also known as the antibiotic class. 

Some of the most commonly prescribed antibiotic classes include:

• tetracyclines
• penicillin
• quinolones
• cephalosporins
• macrolides
• lincomycins
• aminoglycosides
• sulfonamides
• carbapenems
• glycopeptides

The class encompasses a group of antibiotics with similar chemical and pharmacologic properties. Because of this, many antibiotics within the same class kill the same or similar bacteria. 

How antibiotics attack an infection varies between classes. Some antibiotics kill the bacteria directly, while others prevent it from growing and multiplying by interfering with protein production or decreasing the bacteria’s cell wall integrity. 

Do Antibiotics Weaken Your Immune System?

Antibiotics have become a staple of treating bacterial infections, and when you feel sick, it’s common to go to the doctor in search of an antibiotic. This is because the antibiotic helps to attack the bacteria, aiding your immune system in negating the infection. 

Knowing how antibiotics work, it is common to think they only benefit the immune system. However, there is a downside to be aware of. 

As we know, antibiotics kill bacteria, which is good in the case of bacterial infection. However, you naturally have bacteria throughout your body, with some of the most diverse areas being the gut, mouth, and (in women) the vagina. These areas of the body rely on good bacteria to function correctly and even to prevent infections from occurring, but this is where antibiotics can interfere. 

How Can Antibiotics Weaken Your Immune System?

When you take an antibiotic, it gets rid of the bacteria causing your infection, but it may also attack the good bacteria in your body. 

One of the roles of this bacteria, specifically the bacteria in the gut, is to support your immune system. So, when antibiotics kill the good bacteria, they can harm your immune system and weaken it. This is especially noticeable when taking antibiotics for illnesses that they are not meant to treat.

Antibiotics are intended only for cases when you are ill with a bacterial infection, not a virus or fungus. If you take antibiotics when you have a virus-related illness, you can suffer from a depressed immune system, worsening your illness as your body’s immune system cannot work to remove the infection. In the cases of viruses, their removal often relies entirely on your body’s immune system, so taking an antibiotic is not only ineffective, but it can also result in you having a longer-lasting or more severe illness.

A problem with this is that some illnesses may result from both a virus or bacteria. For example, strep throat, bronchitis, and pneumonia can all result from a virus or bacteria, yet only cases resulting from bacteria will benefit from antibiotics. Otherwise, taking antibiotics will not only be ineffective against your illness, but by suppressing your immune system it may make your infection worse.

How Can You Strengthen Your Immune System?

As we know, antibiotics can harm the good bacteria in your gut, but you can help to counteract this effect by taking probiotic shots while on antibiotics. The probiotic shots help replenish the good gut bacteria, helping your body’s natural immune system stay strong. 

Other supplements may help strengthen the immune system, such as vitamin C, elderberry, echinacea, and zinc. Research has shown that these supplements may help improve the immune system, which can help counteract the effects of antibiotics. 

Even more, some of these supplements may also help fight viruses because they help improve the immune system. For example, echinacea and elderberry exhibit antiviral properties in research studies. Elderberry, in particular, blocks the proteins viruses need to enter cells and can keep infected cells from releasing the virus. 

Elderberry also works with Vitamin C by helping your body absorb it better, and by contributing to the immune system, Vitamin C can then help improve it. 

FAQ

Key Takeaways

Antibiotics are a key prescription medication used to treat bacterial infections. However, because they attack bacteria, they can also attack the good bacteria that naturally reside in the body and play an essential role in the immune system. As such, antibiotics can weaken the immune system.

When treating a bacterial infection, this is often not a concern as the benefits offered by antibiotics outweigh the temporary suppression. However, if you take antibiotics for a viral infection, which they cannot treat, you then suppress your immune system and may experience a longer and more severe infection.

If you take antibiotics, there are supplements you can take to boost your immune system, such as probiotics, elderberry, echinacea, zinc, and vitamin C. 

Sources:

• Patel P, Wermuth HR, Calhoun C, et al. Antibiotics. [Updated 2023 May 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535443/ 
• Mocanu, M., & Amariei, S. (2022). Elderberries—A Source of Bioactive Compounds with Antiviral Action. Plants, 11(6), 740. doi: https://www.doi.org/10.3390/plants11060740    
• Hudson, J., & Vimalanathan, S. (2011). Echinacea—A Source of Potent Antivirals for Respiratory Virus Infections. Pharmaceuticals, 4(7), 1019-1031. doi: https://www.doi.org/10.3390/ph4071019 
• Carr, A., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211. doi: https://www.doi.org/10.3390/nu9111211 
• Shekhar, S., & Petersen, F. (2020). The Dark Side of Antibiotics: Adverse Effects on the Infant Immune Defense Against Infection. Frontiers In Pediatrics, 8. doi: https://www.doi.org/10.3389/fped.2020.544460 
• Fehervari, Z. (2018). Antibiotics–immune system interactions. Nature Immunology, 19(2), 99-99. doi: https://www.doi.org/10.1038/s41590-017-0041-7