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Several conditions may cause a bad smell in the nose, including sinusitis, tooth/ mouth infections, dry mouth, some medications, some foods/drinks, and olfactory damage. Typically, a bad smell in the nose is not life-threatening but can decrease the quality of life.

Acute or Chronic Sinusitis

Sinusitis is an inflammation of the sinuses, leading to nasal congestion, bad breath and nasal discharge. These symptoms collectively can cause a foul smell in the nose. Sinusitis can be acute (short term, lasting 3-8 weeks) or chronic (long term.) It is typically caused by a strain of bacteria but can also be caused by a virus or fungus. 

Dental Conditions 

Tooth infections, cavities and poor oral hygiene can all lead to a bad smell in the nose and a bad taste in the mouth. Plaque and bacteria have an odour and can travel through the mouth and reach the sinuses. Tooth decay traps bacteria that release gases that can also produce an unpleasant odour. 

Certain Foods/ Drinks 

The ability to taste and smell is due to microscopic molecules in foods and drinks that travel to the sinuses through passageways in the mouth. Some foods can linger in the mouth and lead to a bad smell in the nose. These foods and drinks include garlic, onions, coffee and spicy foods.   

Certain Medications 

In much the same way as foods and drinks, some medications can also lead to a bad smell in the nose. These medications include nitrates and nitrites, amphetamines and phenothiazine. 

Dry Mouth 

Dry mouth occurs when there is not enough salivary production. Dry mouth symptoms are feeling parched, swollen nasal passageway, sticky mouth, cracked lips and a bad smell in the nose. Causes of dry mouth include dehydration, certain medications, old age, and salivary gland conditions. 

Smoking/ Tobacco Use 

Tobacco use can cause bad breath, and it can also alter the way tastes and smells are perceived, which can cause a bad smell in the nose. 


This is a condition in which people smell certain odours that aren’t there. Often these odours are burning, metallic, chemical or rotten. Phantosmia is associated with colds/flus, sinus infections, migraines, epilepsy and stroke. 

Acid Reflux 

Some digestive conditions, such as acid reflux, can cause a foul smell in the nose and a bad taste in the mouth. Some more serious conditions can also be related to a bad smell in the nose, such as diabetes, liver disease and kidney disease. 

The treatment for a bad smell in the nose is based on the cause. Some home remedies include a daily salt-water rinse, staying hydrated, and practicing good oral hygiene care at home. You can also use over-the-counter medications such as nasal decongestant spray and antihistamines. It is essential to see your doctor/dentist if the bad smell lingers for several weeks or more, as it may be a sign of an underlying condition. Contact us for more information.