Metallic Taste in Mouth or a Bad Taste That Lingers: What Your Teeth and Gums Can Tell You

Which dental problems cause a metallic taste in mouth?

Gum inflammation is the most common dental source. Gums affected by gingivitis or periodontitis bleed easily, and even a small amount of blood mixed with saliva tastes of metal. You may notice it after brushing or first thing in the morning. Our page on bleeding gums explains why plaque at the gum line causes this and why brushing more gently is not the answer.

Infection produces a salty or foul taste. A tooth whose nerve has died can form an abscess that drains through a small spot on the gum, releasing pus into the mouth. Deep gum pockets and a swollen gum around one tooth do the same. The taste often comes and goes as the infection drains and refills.

Wisdom teeth trap food and bacteria. When a wisdom tooth is only partly through, the gum flap over it collects debris and can become inflamed, known as pericoronitis, with a bad taste, a sore gum and sometimes difficulty opening the mouth. When saliva is reduced, as in dry mouth, all of these tastes linger longer.

Old fillings and crowns can leak. A filling or crown with a gap at its edge lets food and bacteria collect underneath, and decay can develop out of sight. Where two different metal restorations touch, a brief metallic tingle or taste is occasionally reported; it is uncommon, and an examination shows whether a restoration is actually failing before anything is replaced.

Medicines, colds and other non-dental causes

Many people with a metallic taste in mouth have perfectly healthy teeth. The NHS lists gum disease alongside several common non-dental causes: certain medicines (it names the antibiotic metronidazole and the sleeping tablet zopiclone as examples), chemotherapy and radiotherapy, colds, sinus infections and other airway problems, indigestion and pregnancy. A change in your sense of smell can also alter taste, because much of what we call flavour is actually smell.

Acid reflux can leave a sour taste and erode enamel over time; see acid reflux and your teeth. A burning feeling rather than a taste is a different problem, covered on our burning mouth page.

If a medicine is the likely cause, speak to the doctor who prescribed it or a pharmacist before changing anything. The taste usually fades once the course ends or your doctor reviews the medicine. If the taste persists without an obvious reason, the NHS advises seeing a GP; a dental examination first is sensible because gum and tooth causes are common and easy to check.