HomeDental ProblemsHalitosis (Bad breath) : What are the Causes, and Treatment

Halitosis (Bad breath) : What are the Causes, and Treatment

Halitosis or bad breath is a malodor or unpleasant smell of breath beyond social acceptance. It not only leads to social embarrassment but also causes harm to your oral health if its cause is pathologic.

Bacterial putrefaction of food debris, protein, and peptides in saliva, gingival crevicular fluid, and plaque forms volatile sulfur substances like hydrogen sulfide and methyl mercaptan which cause bad breath.

Responsible gram-negative bacteria: Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Tannerella forsythia, and spirochetes.

Responsible gram-positive bacteria: Streptococcus salivarius, Solobacterium moorei.

“One in every 4 individuals is affected because of bad breath or halitosis.”

Causes of Bad breath or halitosis :

In most cases, causative factors are found in the mouth or oral cavity in above 90% of cases; however, certain systemic diseases and conditions such as diabetes and hormonal changes respectively cause halitosis.


1. Poor oral hygiene:

It is a common cause of halitosis. It increases bacterial growth in the mouth and causes bad breath.

Tongue coating is the most common cause because of poor oral hygiene. The rough Tongue surface (specifically the dorsal posterior surface) provides room for bacteria growth and food debris, and it remains escaped from normal oral hygiene if properly not cleaned. It causes the formation of a coating on the tongue which is the responsible factor in most cases of bad breath or halitosis.


“Tongue coating because of poor oral hygiene is one of the most common causes behind halitosis or bad breath.”

In cases like crowding teeth, it becomes hard to maintain proper oral hygiene. Apart from that, patients wearing dentures may develop infection and bad odor if oral hygiene is not maintained.

2. Oral Disease :

Certain periodontal diseases like Acute necrotizing ulcerative gingivitis, Chronic periodontitis, Pericoronitis, Dry mouth, Dry socket, etc. are things that may produce bad breath or malodor. You should consult your dentist to know the actual cause.

3. Food :

Certain food items like onion, garlic, etc. temporarily cause bad breath because their breakdown causes the traveling of responsible substances in the blood and then the lung causing bad breath.

4. Medications :

Certain medicines like metronidazole cause bad breath.

5. Diabetes :

In diabetes mellitus, the accumulation of ketones causes sweet fruity-smelling breath.

6. Hormonal changes :

In the menstrual cycle, specifically a day around ovulation, volatile sulfur substances increase in the breath causing odor in breath.

7. Ear, nose, and throat infections :

Tonsillitis, tonsil stones, acute pharyngitis, Ozena, etc. Such infections cause bad odor or halitosis.

8. Lungs and bronchial infections :

Infections like bronchitis, pneumonia, pulmonary abscess, lung cancer, and bronchiectasis may develop a bad odor in breathing.

9. Kidney disease :

In cases of Chronic glomerulonephritis, dimethylamine and trimethylamine increase causes a fishy odor of the breath.

Treatment of Halitosis or Bad breath :

Good oral hygiene practices :

Tongue scraping or cleaning

Good oral hygiene is an important key factor for preventing many oral diseases and also treating halitosis or bad breath. The tongue coating (which contains bacteria and food debris) is the major cause of bad breath or halitosis which is why it is important to clean the tongue with a tongue scraper to remove tongue coating.

The posterior part (back side) of the tongue contains more coating so it should be properly cleaned; initially, it may be difficult because of the gag reflex but gradually you become habituated.

Regular brushing (twice a day) with a soft-bristle brush, use of mouthwash (ask your dentist about mouthwash requirements), and flossing is also important for better oral hygiene maintenance.

Treating existing disease that causes bad breath :

Oral diseases like Acute necrotizing ulcerative gingivitis, Chronic periodontitis, Pericoronitis, Dry mouth, Dry socket, etc. Visit your dentist to find and treat such disease.

Masking Malodor/Bad breath :

It is a temporary solution to mask bad breath using pleasant-smelling sprays, lozenges, and mouth rinses. It doesn’t remove the causative factor but masks bad breath temporarily.

Visit your dentist if you are suffering from bad breath to find out the actual cause of your bad breath to treat it well. In some cases, bad breath occurs due to systemic diseases or conditions, so it is important to consult your dentist.

  1. Scully C, el-Maaytah M, Porter SR, Greenman J. Breath odor: etiopathogenesis, assessment and management. Eur J Oral Sci. 1997 Aug;105(4):287-93. doi: 10.1111/j.1600-0722.1997.tb00242.x. PMID: 9298358.
  2. Journal of the American Dental Association (1939), 01 Apr 1996, 127(4):475-482
Dr.Shubham G. Devaiya, BDS
Dr.Shubham G. Devaiya, BDS
Dr. Shubham G. Devaiya is a registered Dentist and Medical content writer. He graduated from the Goenka research institute of Dental science college with a Bachelor of Dental Surgery (BDS) degree.




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Disclaimer : All the information on the page is for educational purposes only to make you aware, you can’t take it as a substitute for medical advice. If you are facing any health issues it is advised to take direct Medical help from medical professionals immediately.