For many of us, mouthwashes are an integral part of oral hygiene. But are these products proven to be effective and what are they really used for? Below we will discuss all you need to know about mouthwashes, whether they are effective or not.

Let’s start by saying that a mouthwash is not essential when teeth are healthy. To ensure good oral hygiene, you should brush your teeth twice a day, for two or three minutes, with fluoride toothpaste. Mouthwash therefore certainly does not replace the daily brushing of teeth, but it can be used as a supplement.

Mouthwash can also expose you to unpleasant effects: change in taste, change in tooth color, disturbance of the balance of healthy bacterial flora in the mouth, increase in blood pressure, etc. Ask for advice from your dentist.

A fluoride mouthwash strengthens tooth enamel. However, in most cases, twice-daily brushing with fluoride toothpaste is more than enough. Brushing your teeth has the big advantage, in addition to the fluoride intake, of removing tartar (precursor of dental plaque) mechanically.

In addition, mouthwashes stay in the mouth for a very short time and the fluoride is quickly spat out.

However, some products may be useful in addition to brushing for those at increased risk of cavities:

  • children or adults with fixed braces
  • anomalies in the development of enamel or incipient caries
  • sensitive teeth (with retracted gums)
  • prevention of root caries

Tooth erosion

Tooth erosion is the breakdown of enamel caused by the action of acids from food and drink or from the stomach. To prevent this erosion, it is important to eat or drink no more than seven times a day and brush your teeth twice with fluoride toothpaste. It is recommended to brush your teeth half an hour to an hour after eating, so as not to enhance the action of acids from food and drink.

Some mouthwashes provide additional protection against dental erosion, but there is little scientific evidence to support this theory. Rinsing the mouth with water after a meal may be just as effective.

Sensitive teeth

Many types of mouthwash tout their benefits on tooth sensitivity. However, there is no formal scientific evidence for this effectiveness.

Dental plaque and gingivitis

There is no scientific evidence to support the effectiveness of mouthwash against dental plaque and gingivitis, and of any additional benefit to brushing teeth. As the liquid only stays briefly in the mouth, any active agents are quickly spat out, or else dissolve in saliva. And these products do not penetrate under the gums, where the inflammation occurs.

The best way to prevent the onset of dental plaque and gingivitis is to brush your teeth thoroughly, possibly in combination with inter-dental cleaning (toothpick, dental floss, a small toothbrush, etc.).

An antimicrobial mouthwash can be used temporarily in addition to or as a replacement for brushing, when brushing is insufficient or difficult, and/or in the presence of an infection. This type of product also eliminates the good bacteria in the mouth, and it should only be used for a limited period of time, and always on the advice of a dentist.

Bad breath

Mouthwash may temporarily mask bad breath (halitosis), but a feeling of freshness does not mean that the problem is fixed. Refreshing the mouth can partially cover up bad breath temporarily, but it does not help.

Bad breath is often caused by bacteria on the back of the tongue. You can remove these bacteria with a brush or a special scraper. Mouthwashes with antibacterial action, mainly those that contain chlorhexidine (like Halita), can possibly help, but they can only be used for a short time.

In case of bad breath, you should consult your dentist (dental infection) or doctor (a symptom of a health problem).

Teeth whitening

Some mouthwashes would make teeth whiter and/or prevent them from yellowing. This action has never been demonstrated. At best, a mouthwash could remove stains caused by foods and drinks (red wine, coffee …), but it won’t make your teeth whiter.

Dry mouth

Dry mouth can have a variety of causes, such as insufficient hydration, taking certain medications, illness, excessive alcohol consumption, medical treatment …

Brushing your teeth well is even more important because a dry mouth increases the risk of cavities. Mouthwash can potentially offer additional protection, but it should not contain alcohol or menthol, as this dries out the mouth even more.

A saliva replacement or a mouth humidifier should be used preferably before going to sleep, before meals, or when it is necessary to speak at length.

Ask your dentist or doctor for advice.


According to a study in the journal Sexually Transmitted Infections, gargling for one minute with a mouthwash may slow down the development of Neisseria gonorrhea, the bacteria that causes gonorrhea. However, it has not been studied whether this reduces the risk of contracting the infection. In addition, only a limited number of gay men have been tested.

Therefore, based on this study alone, we cannot say that mash washes (in this case Listerine) can prevent gonorrhea.

The alcohol

Many mouthwashes contain alcohol, with antibacterial and flavor-enhancing functions. The alcohol content can exceed 20%, which is higher than many drinks, and it can cause mucosal irritation and dry mouth. It is best to use alcohol-free mouthwash, and this is highly recommended for:

  • children and adolescents
  • pregnant women
  • former alcoholics
  • patients suffering from inflammation of the oral mucosa (mucositis), especially following chemotherapy or radiotherapy
  • people affected by a dry mouth

Ask your pharmacist for advice and/or read the package leaflet carefully.

Oral cancer

Some studies suggest that mouthwashes that contain alcohol increase the risk of getting oral cancer. But this research presents many methodological problems, and this association has certainly not been convincingly demonstrated. If there were to be a link, the risk is in any case minimal.

Nonetheless, always follow the instructions for use and/or your dentist’s instructions.

Additional recommendations

  • Some mouthwashes, such as products that contain chlorhexidine, can only be used for a limited time (usually 1 to 2 weeks).
  • Use the mouthwash once or twice a day. Keep it in the mouth for at least 30 seconds to 1 minute, and circulate it well throughout the mouth. Spit out the product after use (be careful not to swallow anything).
  • Use mouthwash after brushing your teeth.
  • Do not drink, eat or smoke within half an hour of using the mouthwash, as this decreases its effectiveness.
Steven Peck

Working as an editor for the Scientific Origin, Steven is a meticulous professional who strives for excellence and user satisfaction. He is highly passionate about technology, having himself gained a bachelor's degree from the University of South Florida in Information Technology. He covers a wide range of subjects for our magazine.