Can a Dirty Toothbrush Actually Make You Sick?
Yes — a contaminated toothbrush can potentially make you sick. Researchers at the University of Birmingham School of Dentistry have found up to 1.2 million bacteria on a single toothbrush, including flu viruses, staph bacteria, E. coli, yeast fungus, and strep. The good news is that with a healthy immune system and proper toothbrush hygiene habits, the risk remains low for most people — but it is not zero.
What Germs Are Lurking on Your Toothbrush?
Used toothbrushes can harbour a surprising range of microorganisms. Studies have identified the following on toothbrush bristles:
- Influenza (flu) virus — can survive on surfaces for hours
- Staphylococcus (staph) bacteria — a common skin and respiratory pathogen
- E. coli — often linked to bathroom contamination
- Yeast fungus — particularly concerning for individuals with weakened immunity
- Streptococcus (strep) — the same bacteria associated with strep throat
- Herpes simplex virus — transmissible through shared toothbrushes
- Pneumonia-causing bacteria — found in moist, warm environments like bathrooms
The bathroom environment itself is a major contributing factor. Bathrooms are warm, moist, and steamy — ideal conditions for bacterial growth. Many toothbrushes are also stored close to the toilet, making them vulnerable to airborne particles released during flushing.
Why Bathroom Storage Is a Problem
Every time a toilet is flushed with the lid open, microscopic droplets can travel up to two metres and settle on nearby surfaces — including your toothbrush. This is sometimes called the “toilet plume” effect. Combined with a damp bristle environment that never fully dries, your toothbrush can become a reservoir for bacteria between brushing sessions.
For families with young children in Calgary NW, this is especially important to address. Children’s immune systems are still developing, making proper toothbrush hygiene a key part of family dental care.
How to Keep Your Toothbrush Clean and Germ-Free
Following a few simple habits can significantly reduce the number of harmful microorganisms on your toothbrush:
1. Wash Your Hands Before and After Brushing
Hand hygiene is the first line of defence. Washing your hands thoroughly before picking up your toothbrush helps prevent transferring bacteria from your hands to the bristles.
2. Replace Your Toothbrush Regularly
The Canadian Dental Association recommends replacing your toothbrush every three months, or sooner if:
- You have recently recovered from a cold, flu, or mouth infection
- The bristles are visibly frayed or worn
- Someone else has used your brush by mistake
3. Alternate Between Two Toothbrushes
Rotating between two toothbrushes allows each one to fully dry between uses. Bacteria thrive in moisture, so a completely dry brush is a safer brush.
4. Store Your Toothbrush Away from the Toilet
Keep your toothbrush as far from the toilet as possible, and always close the toilet lid before flushing. Store brushes in an upright position and allow them to air dry — avoid sealing them in closed containers, which can encourage mould growth.
5. Never Share Toothbrushes
Sharing a toothbrush is one of the most direct ways to transmit oral bacteria and viruses, including the herpes simplex virus and strep bacteria. Each person in the household should have their own clearly identified brush.
6. Keep Toothbrushes Separate
Even storing brushes too close together can allow bristles to touch and cross-contaminate. Use individual holders or a toothbrush organiser that keeps each brush separated.
7. Rinse Thoroughly After Every Use
After brushing, rinse your toothbrush under running water to remove toothpaste, food debris, and loose bacteria. Shake off excess water and store upright to dry.
When Should You See a Dentist?
If you are experiencing persistent mouth infections, gum irritation, or recurring illness that may be linked to oral hygiene, it is worth speaking with your dental team. Regular professional teeth cleaning in Calgary helps remove bacterial build-up that brushing alone cannot address, supporting both your oral health and your overall wellbeing.
Your dental hygienist can also assess your gum health and flag early signs of concerns during your routine visit. Learn more about our dental hygienist services in Calgary.
Protect Your Family’s Health — Start with the Basics
Good toothbrush hygiene is one of the simplest and most overlooked aspects of staying healthy. By replacing your toothbrush regularly, storing it properly, and keeping brushes separate, you can significantly reduce the bacterial load your family is exposed to every day.
At Expressions Dental in Calgary NW, our licensed dental team is here to support your family’s complete oral health — from everyday hygiene guidance to comprehensive preventive care. If you have questions about your oral hygiene routine or are due for a cleaning, contact us today to book an appointment. We welcome new patients and families across Calgary NW.
Frequently Asked Questions
Can a toothbrush really make you sick?
Yes, it is possible. Research from the University of Birmingham found up to 1.2 million bacteria on a single toothbrush, including flu viruses, staph, E. coli, and strep bacteria. For most healthy people, the immune system provides adequate protection, but those with weakened immunity are at higher risk. Replacing your toothbrush regularly and storing it properly greatly reduces this risk.
How often should I replace my toothbrush?
You should replace your toothbrush every three months, or sooner if the bristles are worn, you have been ill with a cold or flu, or someone else has used it. Frayed bristles are less effective at cleaning teeth and can harbour more bacteria. Your dental hygienist can remind you at your regular check-up.
Should I replace my toothbrush after being sick?
Yes. After recovering from a cold, flu, strep throat, or any oral infection, replace your toothbrush immediately. Continuing to use the same brush after illness can reintroduce the same pathogens into your mouth and potentially delay your recovery or cause reinfection.
Is it safe to store toothbrushes together in the same holder?
It is not ideal. When toothbrush bristles touch, they can transfer bacteria between brushes, which is particularly concerning if someone in the household is unwell. Use a toothbrush holder that keeps each brush separated, and ensure each family member has a clearly labelled brush.
Does closing the toilet lid really help protect my toothbrush?
Yes. Flushing with the lid open can release a fine aerosol mist — often called a "toilet plume" — that can travel up to two metres and settle on nearby surfaces, including your toothbrush. Closing the lid before flushing and storing your toothbrush as far from the toilet as possible significantly reduces this type of contamination.
Is an electric toothbrush more hygienic than a manual one?
Both types can harbour bacteria if not cared for properly. With an electric toothbrush, replace the brush head just as frequently as you would a manual brush — every three months or after illness. Rinse the head thoroughly after use and allow it to air dry in an upright position away from the toilet.
How does professional teeth cleaning help with oral bacteria?
Professional teeth cleaning performed by a licensed dental hygienist removes hardened plaque (tartar) and bacterial build-up that cannot be eliminated by brushing and flossing alone. Regular cleanings at a dental clinic like Expressions Dental in Calgary NW help prevent gum disease, reduce overall oral bacteria levels, and support your general health.