Intestinal and emotional factors, wearing a mask, poor oral hygiene… there are many reasons for having bad breath (halitosis).

However, most often, bad breath is caused by the release through the mouth of sulfur compounds mixed with the air we breathe. The sulfur compounds that give this bad odor come from anaerobic bacteria, that is, bacteria that do not need oxygen to proliferate. These bacteria hide in the folds of the tongue, in infected gums, or between the teeth, in case of poor hygiene or a decrease in the amount of saliva.

People with bad breath, or halitosis in the medical lexicon, are often the last to know. However, between 25 and 50% of the population would be affected by the problem.

Let’s take a look together at the reasons why you might have bad breath.

Poor oral hygiene

In the vast majority of cases, the bad smell is caused by poor oral hygiene. If the mouth is not cleaned well, bacteria grow and create bacterial plaque. This material is composed of bacteria, which on contact with the gum, create a chemical reaction that gives bad breath.

It is recommended to brush your teeth daily at least twice a day–in the morning and at night before going to bed. You should also perform descaling at least once a year.

Gingivitis or periodontitis

Gingivitis is an inflammation of the gum caused by the presence of bacteria, which infiltrate the bone at the root of the tooth and destroy it. If left untreated, it can develop into periodontitis, the gums are severely damaged, and the teeth may loosen. These stagnant and unremoved bacteria are the cause of bad mouth odor. Pregnancy, smoking, menopause can cause gingivitis to develop.

What treatment?

Good oral hygiene can reduce and prevent the development of gingivitis:

  • First, go to the dentist to diagnose the gingivitis and check its progress by measuring the depth of the gum-dental groove, the space between the gum and the tooth. The specialist will take the opportunity to perform a descaling (to be carried out at least once a year).
  • Finally, remember to brush your teeth 2 to 3 times a day for at least 2 minutes as recommended by health experts. You can add a little sodium bicarbonate powder (baking soda) to your toothpaste which can help against bad odors.
  • Do not forget to floss to remove food residues that can also be the cause of bad odors if they remain in the mouth for too long. Amino acids from protein in food actually give the breath a sulfurous odor.

A loaded tongue

Bad odors can also come from bacteria on the tongue. The top of the tongue, poorly supplied with saliva, can actually cause bacteria to rot.

What treatment?

You can use mouthwashes daily to refresh your mouth with menthol or fluoride. There are other products whose components (especially tin fluoride) inactivate bacteria and slow down bacterial metabolism and thus prevent the formation of malodorous substances. You should use them for up to ten days at a time so as not to unbalance the oral flora.

Also, remember to scrub or scrape your tongue. Scraping the tongue is done from back to front to remove the bacterial deposits that cover it. Never use the bristles of the brush as they may create micro lesions on the tongue where bacteria could slip in.

Abscess and tooth decay

Tooth decay, abscess, and the crater left by tooth extraction can be a source of bacteria. Regular dental check-ups are necessary to detect diseased or decayed teeth.

What treatment?

Treat decayed teeth properly and wash your mouth regularly. If the infection is declared, the doctor will extract the tooth or treat the abscess. Often the dentist will also prescribe an antibiotic for ten days to eradicate the infection.

Badly maintained dentures

Badly cleaned or worn for too long, dental prostheses (dentures) can give off very bad odors over time and cause bad breath. Especially if you tend to keep it in your mouth overnight. Once again, the bad smell comes from the bacteria that remain nestled in the recesses of the prosthesis.

What treatment?

  • Maintain impeccable hygiene by reviewing the cleaning instructions of your dentures.
  • Don’t wear your dentures for more than 24 hours at a time.
  • Clean them after each meal by brushing them with a toothbrush and toothpaste.
  • Every evening, immerse the dentures in an antiseptic bath for at least 15 minutes.

A gastric acid problem

When the lower esophageal sphincter (the valve-like muscle between the stomach and the esophagus) is defective, the acid contained in the stomach (used for digestion), goes back up to the mouth along the digestive tract, often giving off a foul-smelling gas.

What treatment?

The doctor will first examine the vocal cords. If they are red and swollen at the back, it is a sign of gastroesophageal reflux disease. He or she will then prescribe an anti-reflux treatment or an anti-secretory acid in the form of tablets to be taken 15 minutes before meals. Often everything gets back to normal after a month of treatment. If not, the specialist will perform more comprehensive examinations, usually by referring the patient to a gastroenterologist to perform a gastroscopy or a pH measurement in the esophagus and stomach. This will allow for the possible diagnosis of an ulcer, gastritis, or esophagitis.

A caseum problem

Sometimes, to find the source of bad breath, you have to take a closer look at your tonsils. Characterized by the presence of white granular tissue on the tonsils at the back of the mouth, caseum is particularly responsible for bad breath. Caseum is manifested by the presence of granular tissue, located after the tonsils, at the back of the mouth. It is a mixture of dead cells and food debris that lodges in the hollows of the tonsils, also called crypts.

What treatment?

By pressing on the tonsils with the handle of a fork, for example, you can probably remove the culprit caseum. But very quickly, over the weeks, the caseum will reform. The radical and definitive solution remains the partial or total removal of the tonsils. The operation is performed either by laser or by surgery under general anesthesia.

Foreign objects in your sinuses

A few foreign objects can nestle deep in the sinuses without you realizing it. This is often the case with the dental paste that the dentist uses during a treatment. Sometimes a little of this residue can pass through the root of the tooth into the sinus. Staying stuck for several days or weeks, they cause bacterial proliferation and over time give off a smelly odor. They can also cause a discharge in the mouth.

What treatment?

The dentist will examine the entrance to the sinuses and the back of the throat. If a yellow, green, or brown discharge is found, the dentist may order a CT scan or a sinus x-ray. Surgery under general anesthesia will then be necessary to remove the dental paste. The purpose of meatotomy is to widely open the sinus in the nose, to allow purulent secretions to drain into the nasal cavity. The operation takes about an hour and requires two days of hospitalization.


Some treatments have the particularity of drying out the mouth. This is the case with antihistamines, antidepressants, antipsychotics, and antihypertensives which act on the parasympathetic nervous system which controls the salivary glands. The saliva rich in antibacterial substances no longer sufficiently irrigates the mouth and bacteria settle in large numbers, accompanied by their foul odor.

What treatment?

Remember to drink water or infusions of peppermint or spearmint regularly to moisten the inside of the mouth and thus help eliminate bacteria. You can also chew sugarless chewing gum throughout the day to promote saliva secretion and/or consume citrus fruits that trigger saliva production.

A bad liver

A problematic liver, heavy meals, a period of fatigue can cause bad breath, which is usually caused by eating foods containing nitrogen. This is the case with proteins. Usually, this nitrogen is eliminated by the liver and kidneys. If the liver is defective, this operation cannot be done. Nitrogen then rises from the stomach to escape through the mouth.

What treatment?

A gastroenterologist will do a blood test to check for liver enzymes and perform a scan of the liver. Bad breath can be a telltale sign of liver failure, cirrhosis, or hepatitis.

At home, make it easier for the liver to work by eating foods that are easy for the liver to process, such as vegetables and fruit. Avoid consuming too much protein.

Take the opportunity to also reduce the consumption of alcohol and tobacco, which are conducive to liver dysfunction.

Hormonal changes during menstruation

Just before menstruation, a hormonal change occurs in women, including the production of more dental plaque which promotes the proliferation of bacteria. This hormonal change also influences the intestinal flora and loads the breath with sulfur.

What treatment?

Remember to have irreproachable dental and oral hygiene by washing your teeth regularly and by performing mouthwashes. This does not treat the real cause of bad breath but may mask it during this short time each month before your period.

High protein diets

High protein diets are useful to lose weight, but they also have the disadvantage of promoting bad breath. In principle, the protein diet is rich in meat, fish, dairy products, eggs, and almost zero carbohydrates. In the absence of carbohydrates, the body will burn fat and release waste products called ketones into the blood. Very volatile, they will also be released in the respiratory tract and cause bad breath.

What treatment?

Be patient and wait until the end of the diet because the smell of acetone in your breath proves that the diet is working. Until then, you can mask the smell with mouthwashes or zero-sugar chewing gums. When you’re done with the diet, eating a reasonable amount of carbohydrates should restore your healthy breath.

Franck Saebring

Franck Saebring is a family man first and a writer second. Born and raised in Frankfurt, Germany, only cars eclipse his love of gadgets. His very passionate about anything tech and science related.