Several conditions may cause a foul smell in your nose, such as nasal polyps, sinus infection, and postnasal drip. A doctor can make a diagnosis and recommend the best treatment.

Almost every day, at least one bad smell finds its way into your nostrils. However, what about bad smells that emanate from your nose?

A variety of health conditions may trigger a rotten smell in your nose. Fortunately, most of these foul fragrances are temporary and not signs of a life threating condition.

That said, you may need to have a healthcare professional examine your sinuses and throat for proper treatment.

Keep reading to learn more about the possible causes of a bad smell in the nose.

Nasal polyps are soft, noncancerous growths shaped like teardrops. They may form on the wall of your nasal cavity or sinuses as a result of chronic inflammation.

Sometimes, you may experience a rotten smell in your nose. This is due to fluid buildup inside the polyps, which comes from the damp lining of your mucous membrane.

Other, more common symptoms of nasal polyps may include:

Nasal polyps tend to be very small, so you may not even know you have them. However, large polyps sometimes form or you may have many small polyps. These could result in blocked nasal passages.

Treatment for nasal polyps may include nasal corticosteroid sprays or drops, such as fluticasone (Flonase) and mometasone (Nasonex).

If they’re ineffective, a doctor may prescribe oral corticosteroids like prednisone for up to 2 weeks. In more serious cases, endoscopic surgery may be necessary.

It’s also important to manage the underlying causes of polyps, such as allergies, infections, or asthma.

Sinus infections, also known as sinusitis, can be caused by viruses, bacteria, or fungi.

Symptoms of sinusitis may include:

Sometimes, you may also experience a rotten smell in your nose. This is usually caused by a buildup of nasal mucus.

Treatment for sinus infections will depend on the type and severity.

For example, treatment for acute sinusitis may include OTC nasal sprays, at-home remedies, and sometimes antibiotics. On the other hand, chronic sinusitis may require prescription steroid medications or antihistamines.

In some cases, you may require sinus surgery.

Smelly mucus in the nose, especially when it thickens and drips incessantly down the back of your throat, is a sign of postnasal drip.

Normally, mucus helps:

  • keep your nasal membranes healthy
  • respond to infections
  • humidify the air you inhale
  • keep foreign particles out of your airways

It mixes with saliva and is swallowed without you being aware of it.

However, a cold, flu, allergy, or sinus infection may cause mucus to thicken, making it harder for it to drain normally.

Postnasal drip may begin mildly, with symptoms of coughing, a sore throat, and frequent swallowing. Sometimes, you may experience foul-smelling nasal discharge from one nostril.

Speak with a healthcare professional if your postnasal drip lasts more than 3 weeks or your foul-smelling mucus is yellow, green, or grey.

Treatment for postnasal drip may include a combination of:

If these remedies don’t help, a doctor may recommend other treatments depending on the underlying cause. These may include:

  • antihistamines for allergies
  • cortisone steroid nasal spray to reduce inflammation
  • antibiotics for a bacterial infection

Tooth decay happens when bacteria collects on a tooth and eats away at the surface. This bacteria buildup may cause bad breath and a bad smell to come through your nose.

Good oral hygiene, which includes brushing your teeth and flossing daily, is the best way to prevent tooth decay and tooth and gum problems.

If a dentist has identified a cavity or another oral problem like periodontitis (gum disease), try to get treatment as soon as possible.

Your tonsils include crevices and folds that can trap:

  • saliva
  • mucus
  • food particles
  • dead cells

Sometimes the debris can harden into tiny objects called tonsil stones. Bacteria can feed on tonsil stones, sometimes generating a bad smell in your mouth and nose.

Poor oral hygiene and unusually large tonsils increase the risk of tonsil stones, but it’s important to note that plenty of people have tonsil stones with healthy oral hygiene.

Some treatment methods for tonsil stones include:

Phantosmia is a hallucination of your olfactory system. This means you smell odors that aren’t there, but you think they’re in your nose or somewhere around you.

Phantosmia can develop after a respiratory infection or a head injury. Conditions like Parkinson’s disease, brain tumors, or inflamed sinuses may also trigger phantom smells in your nose.

For some people, phantosmia resolves on its own. For others, treating the underlying cause of phantosmia may help eliminate the bad smell sensation.

Chronic kidney disease (CKD) is a progressive loss of kidney function.

Your kidneys are responsible for filtering waste products from your blood, which are then excreted in urine. If the kidneys aren’t functioning well, waste materials may build up in the body.

These materials may produce an ammonia-like smell that you could notice in your breath and the taste in your mouth. As a result, you may also have an ammonia-like smell in the back of your nose.

This development usually occurs only after CKD has advanced to stage 4 or stage 5.

It’s important to note that at this point you’ll also have other symptoms, such as kidney pain, changes in urine color, and fatigue. A new ammonia smell probably won’t be the first sign of kidney trouble.

A loss of smell is a symptom of COVID-19.

However, the authors of a 2022 article suggest that some people may even experience a distorted sense of smell. This condition is known as parosmia.

Examples of parosmia may include food smelling bad or perceiving cigarette smoke in a house despite there being no history of smoking.

This condition could gradually worsen, which may have severe health implications. For example, the authors suggest that some people perceive food as smelling rotten. This may then lead to someone eating much less.

COVID-19-related parosmia may occur 3 months after the initial viral infection. The parosmia may be caused by alterations that occur as damaged olfactory receptors regenerate after a loss of smell.

There isn’t a single treatment for COVID-19-related parosmia. However, a healthcare professional may recommend olfactory training therapy.

Speak with a healthcare professional if:

  • the bad smell in your nose lasts for more than 1 week
  • you frequently experience a bad smell in your nose
  • you experience other symptoms, such as facial swelling, nasal obstruction, blurred vision, and headache

If you don’t already have a primary care doctor, our Healthline FindCare tool can help you connect to physicians in your area.

How do I get rid of the rotten smell in my nose?

Treatment for a rotten smell in your nose will depend on the underlying cause and other symptoms. A treatment plan may include at-home remedies like steam inhalation, OTC nasal sprays, prescription medications, or in rare cases, surgery.

Why do I smell something dead in my nose?

A bad smell in your nose may be caused by several health conditions, such as sinusitis, nasal polyps, and tooth decay. Speak with a healthcare professional, as they could provide a proper diagnosis and treatment plan.

Can a sinus infection smell like poop?

A sinus infection may cause an accumulation of nasal mucus to block your nose. Without treatment, bacteria could build up and cause a foul smell that may resemble poop.

What does a nose infection smell like?

A nose infection may not produce any smells because it often blocks your nose, in fact reducing your smell. That said, a build-up of mucus could cause a foul-smelling odor.

A bad smell inside your nose may have several causes. However, most of the time these can be treated with at-home remedies and OTC medications.

If you’re prone to frequent sinus infections, you may encounter these unpleasant episodes repeatedly.

Talk with a doctor about how you can lower your risk for nasal and throat problems down the road.