What causes loss of taste?

Taste and smell work together, so congestion can make food seem flavourless even when the taste buds are working. A common cold may reduce flavour while the nose is blocked. COVID-19 can affect taste or smell during the infection, and altered taste may persist for some people afterwards as part of Long COVID. Dry mouth, oral infections, gum problems, smoking, head injury and some medicines can also change taste. Less often, a nerve or neurological problem is involved.

Notice when the change began and whether it followed a cold, new medicine, dental problem or head injury. Keep drinking fluids, maintain oral hygiene and avoid smoking. Do not stop a prescribed medicine without advice; ask the prescriber whether taste change is a known effect or whether an alternative is suitable. If congestion is present, treating the underlying illness may allow taste to return as the nose clears.

Arrange a medical assessment if loss of taste is persistent, keeps returning, affects eating, or has no clear explanation. Seek urgent help after a head injury if it occurs with weakness, confusion, severe headache or trouble speaking. Get prompt advice for facial drooping, difficulty breathing, or dehydration. A clinician may review medicines, examine the mouth and nose, and test smell, taste or related nerve function.

Could a medicine, mouth problem or nasal blockage explain the change? Does the timing fit an infection such as a common cold or COVID-19? Should my smell and taste be tested, and how long should I monitor recovery?