Strange Taste in Mouth: Blood-Like Taste, Tasteless Tongue and Other Changes

Taste depends on the tongue, saliva and the sense of smell working together. Disturb any of them and food or the mouth itself can taste odd. After a cold, sinus infection or allergy, taste changes are common and usually settle as the illness does.

In the mouth, plaque, a coated tongue, gum disease, a decayed or infected tooth and a dry mouth are the usual causes. Smoking and tobacco dull taste and leave their own flavour, and many medicines and supplements change taste. Our page on bad breath explains why bacteria on the tongue and gums are such a common source.

For a specific taste, see our guides on bitter taste in the mouth and metallic taste in the mouth.

A blood-like taste almost always means a little blood from the gums, even when you cannot see it. Inflamed gums, brushing too hard, a mouth ulcer, a recent extraction or a sore under a denture can all do it. Our page on bleeding gums explains what to do.

Less often the source is the nose or throat, for example after a nosebleed, with a sinus infection or a chest infection that brings up blood-streaked mucus. Coughing up blood, or repeated blood in the mouth without a clear dental cause, needs a doctor promptly.

Loss of taste is most often caused by a blocked nose, since much of what we call taste is smell. A cold, flu, allergy or sinus infection is the common reason, and taste returns as the nose clears.

Other causes include dry mouth, smoking and tobacco, a thick coating on the tongue, burns from hot tea or food, mouth thrush, some medicines, low zinc or other nutrient deficits, and ageing. Our guide on white tongue covers coatings and thrush. A cleaned tongue and a moist mouth often bring taste back.

See a doctor if taste has not returned within a few weeks, or if smell is lost as well without a cold.

A sudden loss of taste or a strange taste together with facial droop, weakness or numbness on one side, slurred speech, severe headache or confusion is an emergency. Go to a hospital emergency department straight away.

A taste change that comes with a dental abscess needs same-day care if there is spreading facial swelling or fever, and hospital emergency care if swallowing or breathing is affected. Otherwise, a new taste that lasts more than two weeks should be seen by a dentist or doctor.