The short answer: A metallic taste that lingers is called dysgeusia. The most common triggers are medicines (such as metformin and metronidazole), colds and sinus infections, dental problems, and early pregnancy. Less often it points to cancer treatment, zinc deficiency, or kidney or liver disease. Most cases fade once the cause is found, but a taste change that lasts, or comes with weight loss or nerve symptoms, should be checked.

What is a metallic taste, medically speaking?

The National Institute on Deafness and Other Communication Disorders (NIDCD) defines dysgeusia as a condition in which a foul, salty, rancid, or metallic taste persists in the mouth. It is different from hypogeusia (a reduced ability to taste) and ageusia (no taste at all). NIDCD also describes phantom taste perception, a lingering unpleasant taste when nothing is in your mouth.

Taste problems are common. NIDCD says more than 200,000 people see a doctor each year for taste or smell problems. It estimates that up to 15 percent of adults might have one.

Smell matters more than most people expect. A 2023 review in American Family Physician notes that when a person only notices a taste problem, the cause is often a smell problem. Flavor depends on both senses working together.

Which medicines can cause a metallic taste?

Medicines are one of the first things doctors check. MedlinePlus lists several drugs that can cause taste problems:

  • Thyroid medicines
  • Captopril, a blood pressure drug
  • Lithium
  • Antibiotics and antifungals such as clarithromycin, rifampin, and griseofulvin
  • Penicillamine and procarbazine
  • Some cancer treatments

Metformin. The FDA-approved label for metformin says about 3 out of every 100 people have an unpleasant metallic taste when they start taking it. The label adds that it lasts for a short time. The same label notes that metformin can lower vitamin B12 levels over time, and MedlinePlus lists B12 deficiency as a cause of taste change.

Metronidazole. This antibiotic treats some bacterial and parasitic infections. Its label states plainly that a sharp, unpleasant metallic taste is not unusual. The label also warns against alcohol during treatment and for at least one day afterward.

If you suspect a medicine, do not stop it on your own. NIDCD notes that stopping or changing a medicine may help, but that choice belongs with the prescriber. Many drug-related taste changes ease with time.

Can pregnancy or pine nuts cause it?

Pregnancy. The UK National Health Service lists a metallic taste in your mouth among early signs of pregnancy. Research on the reason is mixed. A 2024 meta-analysis of 20 studies found that measured taste function did not differ much between pregnant and non-pregnant people, while smell did change. That fits the idea that part of the "taste" shift comes from smell. If you could be pregnant and notice a new metallic taste, a pregnancy test is a sensible first step.

Pine nuts. "Pine mouth" is a strange but real cause. Between July 2008 and June 2012, the FDA received 501 consumer reports of prolonged taste changes after eating pine nuts. People described a bitter or metallic taste starting hours to days later that came back with any food. FDA scientists linked the reports to the species Pinus armandii. The taste lasted up to a few weeks in some cases and went away without serious harm.

A small Danish trial reproduced the effect. Four of six volunteers developed the classic bitter, metallic taste one to two days after eating six to eight suspect nuts.

Do infections and mouth problems play a role?

Yes, and these are among the most common causes. NIDCD lists upper respiratory and middle ear infections as causes of taste disorders. MedlinePlus adds the common cold, flu, sinusitis, nasal polyps, strep throat, and salivary gland infections. For taste problems from a cold or flu, MedlinePlus says normal taste should return when the illness passes.

COVID-19. The AAFP review reports that smell and taste problems occur in 40% to 50% of people diagnosed with COVID-19. A 2025 systematic review of 104 studies found dysgeusia in 32% to 59% of people with COVID-19, along with high rates of dry mouth.

Mouth and dental problems. NIDCD names poor oral hygiene and dental problems as causes. MedlinePlus lists gingivitis (swollen gums), dry mouth, and heavy smoking. Dry mouth matters because saliva carries flavor to taste buds. A dentist can look for gum disease, infection, or a failing filling.

Zinc and B12. MedlinePlus lists vitamin B12 or zinc deficiency as causes of taste change. Zinc pills are not a sure fix, though. The AAFP review says studies on zinc did not show consistent benefits. A blood test can show whether you are low before you try supplements. supplements.md covers how to judge supplement claims.

Cancer treatment. The National Cancer Institute says chemotherapy drugs may cause an unpleasant chemical or metallic taste. Radiation to the head and neck can also change taste. NCI suggests switching to plastic utensils and non-metal cookware if food tastes metallic.

Can a metallic taste signal kidney or liver disease?

It can, but rarely on its own. In these conditions, taste change usually shows up alongside other symptoms.

Kidney disease. A 2025 systematic review found that taste changes in chronic kidney disease are tied to upper digestive symptoms and malnutrition. It also pointed to zinc deficiency in people on dialysis. A 2017 study of people with advanced kidney disease found that a metallic taste became more likely with age. MedlinePlus lists later signs of chronic kidney disease such as breath odor, swelling of the hands and feet, vomiting, and frequent hiccups.

Liver disease. A 2025 review reports taste disturbances in viral hepatitis, cirrhosis, Wilson's disease, and fatty liver disease. Taste problems worsened as liver function declined. Zinc deficiency was the most consistent factor across studies.

A new metallic taste with fatigue, swelling, yellow skin, or dark urine deserves prompt blood work. Tests for kidney and liver function are simple and widely available.

How do doctors evaluate a metallic taste?

Most workups start with questions, not scans. MedlinePlus says a provider will ask how long the problem has lasted, what medicines you take, and whether you have had a recent illness or injury. They will also ask about smoking, smell changes, and other symptoms. Keeping a short log helps. Our symptom journaling guide shows what to track.

The AAFP review describes a typical exam. It includes a look inside the nose, an exam of the mouth, and a check of the head and cranial nerves. A CT scan of the sinuses may help in some cases. Further testing is often unnecessary.

An ear, nose, and throat specialist can measure taste directly. NIDCD says an otolaryngologist can find the lowest concentration of a taste you can detect, sometimes with a "sip, spit, and rinse" test.

Red flags. The AAFP review says MRI of the head with contrast is warranted in three situations:

  • A history of head injury
  • An abnormal neurologic exam, such as facial weakness or numbness
  • Suspicion of a tumor

Also see a doctor soon if the taste change comes with unexplained weight loss, a mouth sore that does not heal, trouble swallowing, or yellowing skin. MedlinePlus advises contacting your provider if taste problems do not go away, or if they occur with other symptoms. For a broader checklist, see when to see a doctor.

The bottom line

A metallic taste usually has an ordinary cause: a new medicine, a cold or sinus infection, a dental issue, early pregnancy, or even a batch of pine nuts. Many of these fade on their own within days to weeks. Review your medicine list first, and keep up with brushing and dental care. See a doctor if the taste lasts more than a few weeks, keeps you from eating, or comes with weight loss, swelling, yellow skin, or new nerve symptoms.

Last updated: September 2026. This article is for informational purposes only and does not constitute medical advice. Talk with your doctor or dentist before stopping a medicine or starting a supplement for taste changes.