Causes, Conditions, Treatment and More


Many causes of a bad smell in the nose, such as the common cold, are easily treatable. However, others may require medical attention, such as digestive disorders and kidney and liver disease.Sometimes a bad smell can come from your environment. However, if the odor does not go away or persists despite the change in environment, it may indicate an underlying health issue.

Read on to find out why you may experience a bad smell in your nose and the treatments. This article also details when to see a doctor.

Yana Bulgakova/Stocksy United

The ability to smell can enhance the enjoyment of food and its taste. However, some foods and drinks can cause a lingering, unpleasant aftertaste or bad smell in the nose. These may include:

  • Garlic
  • onions
  • certain spices
  • alcoholic beverages
  • coffee

If you notice an unpleasant odor after eating a certain food, consider limiting the foods in your diet. If the unpleasant odor persists, contact a doctor for further advice.

Dental conditions and poor hygiene

Tooth decay, also known as tooth decay, occurs when bacteria that induce cavities make your mouth acidic. Acid can break down the surface of teeth and lead to cavities.

Cavities can trap food and bacteria, causing unpleasant odors. These odors can travel up the back of your throat and into your sinuses, causing your nose to smell bad.

Periodontal disease, or gum disease, can also cause an unpleasant smell. It occurs when plaque – a thin, sticky layer of bacteria – builds up on the teeth and hardens.

Without treatment, dental and gum conditions can lead to pain and tooth loss.

Contact a dentist if you suspect you have a condition affecting the health of your teeth or gums. Fillings or fluoride treatments can help.

Good dental and gum hygiene is also important for treating and preventing infections and cavities. This may include brushing your teeth twice a day and flossing regularly.

Phantosmia describes the sensation of sensing something that is not there. Parosmia refers to when you perceive real scents differently, such as smelling dirt when you smell food.

Both parosmia and phantosmia can cause you to detect a bad smell.

Both are olfactory (smelling) dysfunctions that occur due to deficiencies in how the nose perceives smells or how the brain processes them. For example, causes of smell disorders include:

  • respiratory infections
  • head injury
  • exposure to certain chemicals can cause olfactory disturbances

COVID-19 is usually associated with loss of smell or anosmia. However, clinicians, including researchers from a 2021 case study, have reported several cases of phantosmia during and after COVID-19 infection.

Some people’s typical sense of smell recovers over time. Others may continue to experience symptoms. Treatment may include treating the underlying cause and training to recover your sense of smell.

Learn more about the causes and treatment of parosmia and phantosmia.

Postnasal drip occurs when mucus thickens or builds up and can drip down the throat. This can happen as a result of an infection or irritation, for example due to:

  • Common cold
  • flu
  • other infection
  • other nasal conditions, such as sinusitis or nasal polyps
  • allergic
  • asthma
  • irritating chemicals
  • cold air

Sometimes postnasal drip can produce smelly mucus. Mucus can trap bacteria, allowing them to grow. Because the nose, throat, and other airways are connected, your nose can detect these smells.

Treatment for postnasal drip will depend on its cause. Options may include medications to resolve an infection or allergic reaction, over-the-counter (OTC) medications, or home care, such as nasal sprays and decongestants.

Learn more about postnasal drip, including its causes and treatment.

Sinusitis is a common condition that refers to inflammation of the sinuses. It is often caused by infection with a virus, bacteria or fungus. Inflammation can cause the sinuses to produce smelly mucus or postnasal drip.

Sinusitis usually goes away in 2 to 3 weeks.

In the meantime, home care methods such as a nasal rinse or decongestant may help relieve symptoms. In some cases, bacterial sinusitis may require antibiotics.

Nasal polyps are small, non-cancerous growths in the soft tissues of the nose or sinus cavities. They can occur due to conditions that cause inflammation, such as rhinosinusitis or allergies.

Small nasal polyps may not cause obvious symptoms. However, large nasal polyps can block the airways and cause other problems such as:

Congestion buildup and possible sinus infection can also cause postnasal drip, leading to bad nasal odor. Nasal polyps can also cause parosmia.

Nasal polyps can sometimes shrink with steroid sprays or allergy medications. Large polyps may require surgical removal.

Tobacco products can weaken your teeth and gums, leading to dental or gum disease that causes odor. Tobacco products can include:

  • cigarettes
  • pipes
  • cigars
  • Electronic cigarettes
  • chew tobacco

Smoking can also lead to halitosis (bad breath) or an unpleasant odor in the nose and mouth due to the decreased amount of saliva in the mouth. Saliva helps keep the mouth clean. Low amounts of saliva can lead to bad breath.

Several other causes can lead to bad odors in the nose, including:

  • Digestive conditions: Conditions such as acid reflux and gastroesophageal reflux disease (GERD) can cause an unpleasant taste or odor in the airways.
  • Tonsil Stones: These are hard and sometimes painful particles of bacteria and debris that get stuck in the crevices of your tonsils, causing an unpleasant odor.
  • Kidney disease: Kidney disease can sometimes cause ammonia odor on the breath because the kidneys may not be able to excrete the ammonia produced by the body.
  • Liver disease: Severe liver disease can cause people to experience a strong, unpleasant odor on their breath.
  • Certain medications: Certain medications can cause disorders of the sense of smell, such as fantosmia or parosmia. These medications can include antibiotics and antihistamines.
  • Foreign body: A foreign body stuck in the nose can cause a bad smell as it begins to accumulate bacteria.

When to Seek Medical Help

Although some cases of bad smell in the nose may be mild, such as a cold, some cases may require medical treatment.

Contact your doctor if:

  • the odor may come from an unpleasant-smelling mucus
  • you have other symptoms of illness, such as:
    • pain or pressure in the head or face
    • fever
    • tooth or gum pain
    • persistent cough
    • symptoms in other parts of the body, for example, stomach pain
  • the smell gets worse, doesn’t get better, or gets better then comes back

Your doctor or dentist will ask you questions about your symptoms and medical history. They will examine your sinuses and the back of your throat. Also, they can refer you to an ear, nose and throat specialist called an “ENT” doctor.

How to Get Rid of Bad Smells in Your Nose Naturally

Treatment involves focusing on the underlying condition. Natural methods will not cure some conditions, such as large nasal polyps.

However, some home care methods may support your healthcare provider’s treatment plan, including:

  • good oral hygiene by brushing your teeth twice a day and flossing regularly
  • salt spray or fog
  • humidifiers
  • adequate hydration
  • avoiding known triggers of your symptoms, such as smoking

If the home care steps don’t work, contact your doctor.

Many conditions that cause bacteria to build up in the mouth or airways can lead to a bad smell in the nose. This includes sinusitis, postnasal drip, and tooth decay. Other causes include certain foods or medications, olfactory disorders, and kidney disease.

Some of these causes may not require intensive medical treatment. Others may need treatment from a doctor. Often, a treatment that improves the underlying cause can help improve unpleasant nose odor.


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