Causas comunes del mal aliento
Revisado por pares por Dr Krishna Vakharia, MRCGPÚltima actualización por Dr Hayley Willacy, FRCGP Última actualización 31 Oct 2022
Cumple con las directrices editoriales
- DescargarDescargar
- Compartir
- Language
- Discusión
- Versión en audio
En esta serie:Halitosis
Most cases of bad breath (halitosis) come from germs (bacteria) or debris that build up within the mouth.
En este artículo:
Videos seleccionados para Cuidado bucal y problemas
Continúa leyendo abajo
What causes bad breath?
Morning bad breath
Most people have some degree of bad breath after a night's sleep. This is normal and occurs because the mouth tends to get dry and stagnate overnight. This usually clears when the flow of saliva increases soon after starting to eat breakfast.
Dry mouth (xerostomia)
Bad breath associated with a boca seca is caused by a reduction in the cleansing mechanism of the mouth as a result of reduced flow of saliva from the salivary glands. There are many causes of a dry mouth contributing to bad breath. The most common cause is after a night's sleep (discussed above). Dry mouth may also occur:
Due to a lack of fluid in the body (deshidratación).
As a side-effect of some medicines (for example, antidepresivos tricíclicos).
As a symptom of some diseases (such as Síndrome de Sjögren).
Following radiotherapy to the head and neck region.
Artificial saliva is available; all can be bought over the counter at pharmacies and some can be prescribed on the NHS for certain conditions.
Foods, drinks and medicines
Chemicals in foods can get into the bloodstream and then be breathed out from the lungs. Most people are familiar with the smell of garlic, spicy foods and alcoholic drinks on the breath of people who have recently eaten or drunk these. Various other foods and medicines can cause bad breath. This type of bad breath is temporary and easily cured by not eating the food.
If a medicine is the cause of bad breath, then discuss possible alternatives with your doctor. Medicines that have been associated with bad breath include:
Betel.
Chloral hydrate.
Nitrites and nitrates.
Dimethyl sulfoxide.
Some chemotherapy medicines.
Phenothiazines.
Amfetamines.
'Water' tablets (diuretics).
Check the list of side-effects on the leaflet that comes with your medicine if you think it might be causing bad breath.
Fumar
Most non-smokers can tell if a person is a smoker by their breath. . Stopping smoking is the only cure for this type of bad breath. Smoking tobacco products also increases the risk of developing gum disease - another cause of bad breath.
Diets
Crash dieting or fasting can cause a sickly sweet smell on the breath. This is due to chemicals called ketones being made by the breakdown of fat. Some ketones are then breathed out with each breath. Low-carbohydrate and keto diets also can cause this sort of bad breath.
Medical causes
Medical causes, other than health problems in the mouth, are relatively uncommon. Possible causes include:
Nasal problems. For example, a lump (polyp) in the nose or a small object stuck in a nostril (occurs most commonly in children) can cause a bad smell. In this situation, the smell tends to occur only, or more severely, when you breathe out through your nose. It is not so noticeable when you breathe out through your mouth.
Throat infections such as amigdalitis.
Mouth infections, such as abscesos dentales.
Infecciones o tumores of the lung.
Reflux of acid from the stomach o a stomach infection called Helicobacter pylori.
Severe kidney or liver problems.
Fish odour syndrome (trimethylaminuria). This is a rare medical cause but worth being aware of. It typically causes breath and body odour that is often like a fishy smell. It occurs because the body loses the ability to properly break down trimethylamine which is found in certain foods. There is then a build-up of trimethylamine in the body which is released in sweat, urine and breath. Urine and blood tests can help to confirm this diagnosis if it is suspected.
In these medical cases, there are usually other symptoms that would indicate the cause. For example, a blocked nose, sinus pain, chest symptoms, a high temperature (fever), etc. If you are otherwise well and have no other symptoms apart from bad breath, the smell is likely to be coming from a build-up of bacteria in the mouth and other medical causes are unlikely.
Bad breath caused by germs (halitosis)
Volver al contenidoIn most people who have bad breath (halitosis), the bad smell is thought to come from germs (bacteria) and debris within the mouth.
As the bacteria break down proteins and other debris in the mouth, they release foul-smelling gases. One or more of the following may contribute to the build-up of bacteria, debris and bad breath:
Food stuck between teeth and gums
Normal teeth brushing may not clear bits of food which can get stuck between teeth. The food then rots and becomes riddled with bacteria. In addition to regular cleaning with fluoride toothpaste, flossing between the teeth (or using interdental brushes) can clear and prevent this problem.
If you wear dentures, they should be removed and cleaned every night.
Plaque, tartar (calculus) and gum disease
Dental plaque is a soft whitish deposit that forms on the surface of teeth. It forms when bacteria combine with food and saliva. Plaque contains many types of bacteria. Calculus is hardened calcified plaque. It sticks firmly to teeth. Gum disease means infection or inflammation of the tissues that surround the teeth. If your gums look inflamed, or regularly bleed when you clean your teeth, you are likely to have gum disease. The severity can range from mild to severe.
There is some evidence that antibacterial mouthwashes (such as those containing chlorhexidine) may also be useful in preventing bad breath. Be aware that these may discolour your teeth or dentures. These can be bought over the counter.
Coating on the back of the tongue
In some people, a coating develops on the back part of the tongue. It is not clear why this occurs. It may be from mucus that drips down from the back of the nose (postnasal drip). The coating can contain many bacteria. This explains why bad breath can sometimes occur in people with otherwise good oral hygiene. It is recommended that the tongue is cleaned every night with a proper utensil (such as a tongue scraper), rather than a toothbrush.
Tonsil stones (tonsilloliths)
Cálculos amigdalinos are are clusters of calcified material that form in the tonsillar crypts, or crevices of the tonsils. They are made up mostly of calcium but can contain other ingredients such as magnesium and phosphorus, and can feel like a small lump in the tonsils. Rarely harmful, they can be a nuisance and hard to remove and can often cause bad breath.
Selecciones del paciente para Cuidado bucal y problemas

Cuidado oral y dental
Candidiasis oral
La candidiasis oral es una infección en la boca causada por un hongo de levadura llamado cándida. No suele ser grave y generalmente se puede eliminar fácilmente con tratamiento.
por la Dra. Philippa Vincent, MRCGP

Cuidado oral y dental
Infección primaria por herpes labial
Tu primera infección (primaria) con el virus del herpes labial puede parecer diferente a las aftas recurrentes que muchas personas tienen. Puede que no haya síntomas, pero a veces puede haber una infección significativa en tu boca. El tratamiento tiene como objetivo aliviar los síntomas mientras la infección se resuelve gradualmente en 1-3 semanas.
por la Dra. Philippa Vincent, MRCGP
Lecturas adicionales y referencias
- Halitosis; NICE CKS, septiembre 2024 (acceso solo en el Reino Unido)
- Izidoro C, Botelho J, Machado V, et al; Revisiting Standard and Novel Therapeutic Approaches in Halitosis: A Review. Int J Environ Res Public Health. 2022 Sep 8;19(18). pii: ijerph191811303. doi: 10.3390/ijerph191811303.
- Jamali Z, Alipour M, Ebrahimi S, et al; Effect of Halita mouthwash on oral halitosis treatment: A randomized triple-blind clinical trial. J Dent Res Dent Clin Dent Prospects. 2019 Winter;13(1):31-35. Epub 2019 Apr 24.
- Acar B, Berker E, Tan C, et al; Effects of oral prophylaxis including tongue cleaning on halitosis and gingival inflammation in gingivitis patients-a randomized controlled clinical trial. Clin Oral Investig. 2019 Apr;23(4):1829-1836. doi: 10.1007/s00784-018-2617-5. Epub 2018 Sep 13.
- Poniewierka E, Pleskacz M, Luc-Pleskacz N, et al; Halitosis as a symptom of gastroenterological diseases. Prz Gastroenterol. 2022;17(1):17-20. doi: 10.5114/pg.2022.114593. Epub 2022 Mar 18.
- Kauss AR, Antunes M, Zanetti F, et al; Influence of tobacco smoking on the development of halitosis. Toxicol Rep. 2022 Mar 6;9:316-322. doi: 10.1016/j.toxrep.2022.02.012. eCollection 2022.
Continúa leyendo abajo
Historial del artículo
La información en esta página está escrita y revisada por pares por clínicos calificados.
Próxima revisión: 30 de octubre de 2027
31 Oct 2022 | Última versión
6 Jul 2017 | Publicado originalmente
Escrito por:
Dr Mary Harding, MRCGP

Pregunta, comparte, conecta.
Navega por discusiones, haz preguntas y comparte experiencias en cientos de temas de salud.

¿Te sientes mal?
Evalúa tus síntomas en línea de forma gratuita
Suscríbete al boletín de Patient
Tu dosis semanal de consejos de salud claros y confiables, escritos para ayudarte a sentirte informado, seguro y en control.
Al suscribirte aceptas nuestros Política de Privacidad. Puedes darte de baja en cualquier momento. Nunca vendemos tus datos.