Smell and taste

Lost or Changed Sense of Smell

Common causes, safety steps and when to get checked.

A practical guide to reduced, lost or distorted smell, including common causes, safety steps, smell training and when to seek medical advice.

Smell and taste7 min readGeneral informationUpdated May 2026

Smell change can be temporary, but persistent, unexplained or one-sided symptoms deserve assessment.

There are different smell changes

Anosmia means loss of smell, hyposmia means reduced smell and parosmia means distorted smell.

Taste is often affected

Much of flavour comes from smell, so food may seem bland even when basic taste is still present.

Safety steps are important

Smoke alarms, gas safety and food-date checks become more important when smell is reduced.

The main smell terms

A change in smell can be surprisingly unsettling. It can affect food, mood, safety, appetite, social confidence and enjoyment of familiar places. People may say that they have “lost taste”, but often the problem is that flavour is reduced because smell contributes so much to flavour.

AnosmiaComplete loss or absence of smell.

HyposmiaReduced sense of smell.

ParosmiaSmells are distorted, often unpleasant or different from expected.

PhantosmiaSmelling something that is not actually present.

Common causes of lost or changed smell

Short-term smell loss is often linked to a cold, flu, COVID-19 or nasal congestion. If the airflow cannot reach the smell area high in the nose, smell may drop. In many people this improves as the infection or congestion settles.

Longer-lasting smell changes can follow viral illness, head injury, chronic rhinosinusitis, nasal polyps, allergic rhinitis, medication effects, smoking, toxin exposure or neurological conditions. Sometimes no single cause is found. Smell can also become less sharp with age.

The pattern helps. A blocked nose with reduced smell suggests airflow or sinus inflammation may be involved. A sudden smell change after a viral illness may be post-viral. Smell loss after head injury deserves medical review. One-sided symptoms, bleeding, crusting or a new nasal blockage should not be ignored.

Smell trainingFor some persistent smell changes, smell training may be suggested. This usually means regularly smelling a small set of familiar odours over weeks to months. It is not an instant fix, but it is low-risk and may help some people relearn smell signals.

Watercolour safety illustration showing smell loss, smoke alarm, food and gas safety cues — Safety matters when smell is reduced: smoke, gas, spoiled food and appetite cues may be harder to detect.

Safety and everyday impact

Smell is an early warning system. If it is reduced, check that smoke alarms work, consider gas safety carefully, follow food storage guidance, use sell-by and use-by dates, and ask someone else to check food or household smells if needed.

Smell change can also affect wellbeing. Food may become less enjoyable, some people lose weight, and others use more salt, sugar or spice to chase flavour. Parosmia can make previously pleasant foods smell burnt, chemical or rotten. It is reasonable to mention the emotional and practical impact when seeking advice; it is not “just a smell problem”.

When to seek medical advice

Seek advice if smell loss is persistent, unexplained, follows a head injury, is associated with one-sided nasal symptoms, bleeding, severe headache, neurological symptoms, facial swelling or significant nasal blockage. Review is also sensible if smell change is affecting eating, safety, work or quality of life.

Urgent symptomsUse urgent care for new neurological symptoms, severe headache, confusion, weakness, facial droop, eye symptoms, head injury concerns, or if you feel seriously unwell.

Sources and further reading

This article is general public information and was written using UK, European and well-regarded US sources. It should not replace personal medical advice.

Lost or changed sense of smellNHS
Smell disordersNIDCD
Anosmia / change in sense of smellRight Decisions / NHS Scotland
Loss of smell causesMayo Clinic
Anosmia / smell disordersENT UK