Metallic taste in the mouth: causes, medicines, pregnancy, fillings and when to seek help

What causes a metallic taste in the mouth?

A metallic taste is a form of dysgeusia, a taste disorder in which a metallic, salty, rancid or simply unpleasant taste persists in the mouth. This is how the US institute NIDCD describes it. It lists causes of taste disorders including upper respiratory and middle ear infections, head and neck radiotherapy, chemical exposure, certain medicines, head injuries, ear, nose and throat surgery, poor oral hygiene and dental disease.

Taste and smell are closely linked: NIDCD stresses that most people who believe they have a taste disorder actually have a smell problem, because food aromas reach the nose from the throat. This is why food may taste different with a cold and a blocked nose. Other taste disorders include reduced taste (hypogeusia), loss of taste (ageusia) and phantom taste, an unpleasant taste when there is nothing in the mouth.

Taste disorders are common. Cleveland Clinic reports that up to 17% of people in the USA may experience dysgeusia during their lifetime, while NIDCD estimates that up to 15% of adults have a problem with taste or smell, although many do not seek medical advice.

Metallic taste: causes, clues and what to do

What accompanies a metallic taste and when it began usually help establish its cause. The table brings together causes described by NIDCD, the NHS and Cleveland Clinic, along with a useful first step.

Blood in the mouth: can a metallic taste come from the gums?

Bleeding gums are one of the first things to check when you have an unpleasant taste in your mouth. The NHS, the UK’s public health service, lists gum disease symptoms including bleeding when brushing, flossing or eating hard foods, swollen and red gums, bad breath and an unpleasant taste.

NIDCD lists poor oral hygiene and dental disease among the causes of taste disorders and stresses that good hygiene is important for regaining and maintaining a good sense of taste. The NHS advises brushing at least 2 times a day with fluoride toothpaste, cleaning between teeth daily with floss or interdental brushes, and seeing a dentist if gums bleed, hurt or are swollen.

According to the NHS, very painful and swollen gums, loose or falling teeth, mouth ulcers or red patches, and a lump in the mouth or on the lip need an urgent dental appointment. Separate articles explain gingivitis and periodontitis.

Metallic taste and fillings: what do we know about galvanic currents?

Oral galvanism occurs when a weak current develops between different metals in the mouth, such as amalgam, gold or titanium, because saliva readily conducts electrical charges. Kim’s 2023 review lists reported symptoms including metallic taste, burning around the teeth, smell disorders and pain in the oral lining or tongue.

However, knowledge of galvanism is limited: the same review acknowledges that measuring and diagnosing it is difficult to integrate into routine practice, and some patients’ symptoms proved to have a psychosomatic basis. A dentist therefore first looks for more common causes, such as gum disease, infection or medicines, and decides about any replacement of metal restorations after examination.

Since 1 January 2025, EU Regulation 2024/1849 has, as a general rule, prohibited dental amalgam use except where a dentist considers it strictly necessary because of a patient’s specific medical needs. Some Member States were able to use a temporary derogation until 30 June 2026. The ban concerns placing new fillings and does not require old ones to be removed automatically (legal status as of 24 October 2026).

Which medicines can cause a metallic taste?

Medicines are a common cause of taste changes: Schiffman’s 2018 review reports that hundreds of medicines can cause an unpleasant taste or smell. Some, themselves bitter or metallic, produce the taste directly. Doty et al. (2008) list blood pressure medicines, antimicrobials and antidepressants among the main groups.

NHS information lists metallic taste as a side effect of the antibiotic metronidazole and of lithium, and altered taste as a common side effect of metformin, a diabetes medicine. Cleveland Clinic adds over-the-counter allergy medicines, antibiotics, antidepressants and chemotherapy.

Schiffman notes that in studies of older people, loss of taste and smell was greatest among those taking the most prescription medicines. Do not stop a medicine because of a taste change: NIDCD stresses that treatment changes should be supervised by a doctor. For metronidazole, the NHS advises drinking plenty of water and eating plain foods you enjoy.

Metallic taste in pregnancy, infection and other conditions

A metallic taste can be an early pregnancy symptom: the NHS lists it among signs that usually appear around weeks 4 to 6. Cleveland Clinic explains that taste disorders are common in pregnancy and usually result from rapid hormonal changes.

According to Cleveland Clinic, viral infections such as colds, flu and COVID-19 affect taste. The NHS lists loss or change of smell or taste among COVID-19 symptoms. Cleveland Clinic reports that in most cases dysgeusia resolves when a clinician finds and addresses the cause, and describes smell training for post-COVID-19 disorders.

Other causes include zinc and B vitamin deficiencies, cancer treatment, nerve damage after ear or neck surgery and kidney disease. A metallic taste together with reduced urine, swollen ankles and feet, tiredness, nausea or vomiting may indicate acute kidney failure and needs urgent help at a hospital emergency department. A metallic taste also sometimes accompanies burning mouth syndrome.

Bitter taste in the mouth: could it be reflux?

A bitter or sour taste has several possible sources, including reflux, in which stomach contents flow back into the oesophagus. The NHS lists heartburn, a burning feeling in the middle of the chest, and an unpleasant sour taste caused by stomach acid among its main symptoms.

Medicines that themselves taste bitter can also cause a bitter taste, as Schiffman’s review notes. See a GP if you have heartburn most days, if lifestyle changes and pharmacy medicines do not help, or if food gets stuck in your oesophagus, you vomit frequently or lose weight without a reason.

When should a metallic taste be checked by a dentist or doctor?

Start with a dentist if your gums bleed, a tooth hurts or you have a new restoration. Start with a GP if the taste appeared after a new medicine, during an infection or alongside other systemic symptoms. An ear, nose and throat specialist diagnoses taste and smell disorders: NIDCD describes examination of the ears, nose and throat, a dental examination, history-taking and taste tests.

• Bleeding, painful or swollen gums: dentist.
• Metallic taste after a new medicine: the prescribing doctor.
• Taste or smell changes persist after infection: GP or ear, nose and throat specialist.
• Heartburn and sour taste most days: GP.
• Missed period: pregnancy test and doctor.
• Metallic taste with reduced urine, swelling and nausea: urgent emergency department assessment.

How it works at DentalBlue

At DentalBlue in Białystok, a clinician assesses the gums, teeth, fillings and prosthetic restorations when investigating a metallic taste, with X-rays taken in the clinic’s own radiology unit if needed. “Wizyta bez bólu” (visit without pain) includes a panoramic X-ray, consultation, examination and written treatment plan (300 zł in the clinic’s price list). If the gums are the source, the price list includes “Konsultacja periodontologiczna” (periodontal consultation) at 300 zł and “Kompleksowa higienizacja (skaling, piaskowanie, fluoryzacja)” (comprehensive cleaning: scaling, air polishing and fluoride treatment) at 350 zł. The final scope and cost are agreed at the appointment, and prices may change.