How Much Bacteria is on Your Toothbrush?


It looks innocent enough, resting in your toothbrush holder, but the bristles of your toothbrush can be a hotbed for bacteria. The goal of brushing your teeth is to remove bacteria that cause gum disease and dental caries, but what if your toothbrush is laden with bacteria? 

What’s on Your Toothbrush? 

A study of used toothbrushes by researchers at the Institute of Microbiology of the Medical Faculty in Skopje found that used toothbrushes have a variety of potentially harmful bacteria on their bristles. The toothbrushes came from 20 studies with healthy dentition and gum. 

The bacterial species they found included bacteria with names like Escherichia coli, Klebsiella, Enterobacter, Serratio, and Pseudomonas. Not all of these bacterial species are destined to make you sick, but it shows the importance of not sharing a toothbrush with anyone else, not even your husband or wife. 

Most bacteria on a toothbrush won’t cause illness if you have a healthy immune system to fight them off, but it could be more of a problem if you have a weakened immune system. 

How Do Toothbrushes Get So Dirty? 

The biggest problems arise when you share a bathroom with other people. When your toothbrush sits around in an environment where several people move in and out and brush their teeth, your toothbrush becomes colonized with bacteria and viruses that aren’t part of the bacteria and viruses your body is accustomed to, as they aren’t part of your normal flora. Since your body isn’t accustomed to these bacteria and viruses, you don’t have immunity against them, and the odds of illness go up. 

“I always remind my patients to not share toothbrush holders with their loved ones. Additionally, place your toothbrush in the holder head up,” says Los Angeles dentist, Shervin M. Louie, DDS.   

One study found 60% of toothbrushes from communal bathrooms with around 9 users contained bacteria found in fecal matter. That’s not what you want to brush your teeth with! You might imagine that covering your toothbrush or placing it in a closed container would help, but that can make matters worse. If you place a damp toothbrush in an enclosed container, the wetness and humidity create an ideal environment for bacteria to grow and proliferate. 

Another “don’t” is to place your toothbrush in line with the toilet. Every time you flush the toilet with the lid open, you shower your toothbrush with fecal bacteria. Ew! That’s why it’s a good idea to store your toothbrush as far away as possible, and not directly in front of it. Also, close the lid when you flush. When you flush, it sends aerosolized bacteria traveling as far as 6 feet into the air. 

It’s Not as Bad as It Sounds 

Before getting too excited and assuming your toothbrush is destined to make you ill, consider this. Your mouth is already teeming with bacteria and there’s no strong evidence your toothbrush can make you sick. The biggest problem would arise if you share a bathroom or a toothbrush with other people and lots of other people brush their teeth in the same sink you do.  

Tips for Keeping Your Toothbrush from Making You Sick 

If you’d like to keep your toothbrush a little less icky, here are some tips for doing so: 

Always wash your toothbrush in warm water before and after using it. If you don’t flush away the food particles from your toothbrush after brushing, the tiny food debris serves as a food source for bacterial growth. 

It goes without saying that you shouldn’t share your toothbrush with anyone else, and it’s preferable to have your own bathroom too. Sharing a bathroom with anyone can get a little too cozy for your health. Also, don’t keep your toothbrush around indefinitely. Retire it after about three months and let a new toothbrush do the job. Also, clean your toothbrush holder at least weekly. It does you no favors to open a fresh toothbrush and place it in a bacterial infested holder. 

Be sure to visit your dentist every 6 months for a professional cleaning, so you can keep your teeth and gums as healthy as possible. A little prevention can save you headaches (or a root canal) later. 


“The Ugly Truth About Your Toothbrush & Germs.” 31 Mar. 2021, 

“(PDF) Bacterial Contamination of the Toothbrushes.” 

“Fecal matter found on more than 60% of toothbrushes in ….” 06 Jun. 2015, 

Karibasappa GN, Nagesh L, Sujatha BK. Assessment of microbial contamination of toothbrush head: an in vitro study. Indian J Dent Res. 2011 Jan-Feb;22(1):2-5. doi: 10.4103/0970-9290.79965. PMID: 21525668. 

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