Symptom guide
Loss of smell and taste: causes, red flags and when to get it checked
Smell and taste are closely linked, so losing smell usually dulls flavour as well. The commonest causes are colds, sinus and nasal problems and viral infections including COVID-19. Many people recover over weeks to months, and smell training can help. Persistent or one-sided loss deserves an ENT assessment.
Last checked: 2026-10-03
Key facts
At a glance.
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Smell drives flavour
Most "loss of taste" is actually loss of smell, as the tongue only senses sweet, sour, salty, bitter and umami.
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Common causes
Viral infections, blocked noses, sinus disease, nasal polyps and head injury are the main causes.
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Recovery
Many people recover over weeks to months after a viral cause, and smell training may help.
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Safety
Smell loss means you may not detect gas leaks, smoke or spoiled food; fit working alarms.
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Who to see
GP; ENT if persistent beyond three months, one-sided or with other symptoms.
What this symptom usually means
Smell relies on nerve endings high inside the nose and a nerve running through a thin bone plate to the brain. Anything that blocks airflow to this area, inflames the lining, or damages the nerve can dull or abolish smell. Because flavour is mostly smell, food seems bland.
Possible causes, from most to least common
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Cold, flu and other viral upper respiratory infections, including COVID-19, where smell loss can occur with little congestion.
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Allergic rhinitis and chronic rhinosinusitis, with or without nasal polyps, causing blocked airflow and inflammation.
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Smoking, and exposure to irritants or some chemicals.
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Head injury, which can shear the smell nerve fibres.
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Age: smell declines gradually, particularly after 65.
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Medicines such as some antibiotics, nasal sprays and ACE inhibitors, and nasal surgery.
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Neurological conditions, including Parkinson disease and Alzheimer disease, where smell loss can be an early feature.
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Rarely, tumours at the base of the brain or in the nose, and hormone or nutritional problems.
Features that point to something more serious
Loss on one side only, bloody nasal discharge, a persistent blocked nostril on one side, facial numbness, double vision, headache with neurological symptoms, or loss that follows a head injury and does not recover warrant specialist assessment.
Red flags: when to seek help
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Call 999: smell loss with sudden weakness, confusion, or facial droop.
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Same-day GP or NHS 111: smell loss with severe headache, high fever, stiff neck or swelling around the eye.
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GP within weeks: one-sided loss, one-sided bleeding or blocked nose, or loss lasting more than three months.
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Routine GP or pharmacist: smell loss with a cold that is improving.
What a doctor will ask and examine
Your doctor will ask when it began, whether it followed an infection or injury, nasal symptoms, smoking, medicines and other neurological symptoms. They will examine the nose for swelling, polyps or obstruction, often with a nasal endoscope, and may test smell with scratch-and-sniff tests.
Tests that are commonly used and why
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Smell identification tests: objective measures of how much smell is lost.
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Nasal endoscopy: looks for polyps, inflammation or masses.
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CT sinuses: for persistent sinus disease or polyps.
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MRI brain and olfactory bulbs: if neurological causes or a tumour are suspected.
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Allergy tests or blood tests where indicated.
Self-care and the usual route
Smell training involves sniffing four distinct scents, such as rose, lemon, clove and eucalyptus, twice daily for several months; evidence suggests it can help recovery after viral loss. Treat nasal allergy and congestion, stop smoking, and take safety steps such as smoke and gas alarms, checking food dates and labelling cooked food.
On the NHS a GP can start treatment and refer to ENT. Privately, ENT consultation, nasal endoscopy and CT or MRI can be arranged directly.
Frequently asked
Questions people ask.
Quick, plain-English answers to the questions we hear most.
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How long does it take to get smell back after COVID?
Many people regain smell within weeks to a few months, but a minority have long-lasting loss. If it persists beyond three months, specialist assessment is advised.
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What is smell training?
Regularly sniffing a set of strong scents, such as rose, lemon, clove and eucalyptus, twice a day for months. It may help the olfactory nerve recover.
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Why does food taste bland?
Flavour comes mostly from smell. Without it, only basic tastes remain, so food seems dull.
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Can a blocked nose cause it?
Yes. Swollen nasal lining or polyps block air from reaching the smell receptors, and treating the blockage often helps.
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Is smell loss an early sign of Parkinson disease?
It can occur years before other symptoms, but smell loss is very common and rarely means Parkinson disease on its own.
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Can nasal sprays help?
Steroid nasal sprays help when inflammation or polyps are the cause. Decongestant sprays should not be used for more than a few days.
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Is it dangerous?
Not in itself, but you may miss gas leaks, smoke or spoiled food, so working alarms and food-date vigilance matter.
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Do I need a scan?
A CT or MRI is considered when loss is persistent, one-sided, follows head injury, or comes with neurological features.
Where this comes from
Sources and checking.
This guide is for information, not medical advice.
Your GP or consultant knows your history and can tell you which parts apply to you. If your symptoms are severe, rapidly worsening, or come with red-flag features, seek urgent medical care. Figures and availability change, so treat them as a guide and confirm with the provider.
Published 2026-10-03, next review 2027-10-03.
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NHS: Sinusitis (nhs.uk/conditions/sinusitis-sinus-infection/)