Why do I have a metallic taste in my mouth?

Doctors call a distorted or persistent unpleasant taste dysgeusia. The NIDCD, part of the National Institutes of Health, describes it as a foul, salty, rancid or metallic taste that lingers in the mouth, and notes that tasting something when nothing is in your mouth (phantom taste) is the most common taste disorder. Cleveland Clinic cites research suggesting up to 17% of people in the US experience dysgeusia at some point.

People describe it as tasting metal, iron, coins, blood or chemicals. These are usually the same problem, so this page also covers a chemical taste. If you can actually see blood when you spit, read our page on the taste of blood instead.

1. Medicines. Cleveland Clinic lists the antibiotics clarithromycin, metronidazole and tetracycline, allopurinol for gout, captopril for blood pressure, lithium, methazolamide for glaucoma and metformin for diabetes. Some drugs are excreted in saliva; others, such as some antidepressants, change taste by drying the mouth.
2. Vitamins and supplements. Multivitamins containing chromium, copper or zinc, zinc cold lozenges, prenatal vitamins, and iron or calcium supplements.
3. Gum and tooth problems. Gingivitis, periodontitis and tooth infections. The taste usually goes once the infection is treated.
4. Colds, sinusitis and COVID-19. Respiratory infections commonly change taste. Cleveland Clinic notes a metallic taste after COVID-19 can last weeks or even months.
5. Pregnancy. Usually worst in the first trimester. See metallic taste in pregnancy.
6. Cancer treatment. Chemotherapy and radiation, especially to the head and neck, often cause a metallic or chemical taste, sometimes called chemo mouth.
7. Pine nuts. "Pine mouth" is a bitter or metallic taste that starts 4 to 48 hours after eating certain pine nuts. The FDA received 197 reports between 2008 and 2010; the taste lasted 5 to 10 days on average and went away without lasting harm.
8. Kidney or liver disease, undiagnosed diabetes and dementia. Uncommon causes that typically come with other symptoms.
9. Chemical exposure. Lead, mercury and some insecticides.

• Keep your mouth clean: brush twice daily, floss, and clean your tongue, since gum infection and coating add to unpleasant tastes.
• Drink water through the day and chew sugar-free gum to keep saliva flowing.
• Cleveland Clinic suggests a baking soda rinse (half a teaspoon in a glass of warm water) to neutralize odor and acidity.
• Check supplement labels for doses above the recommended amount, and avoid doubling up across products.
• If a needed medicine is the cause, ask whether timing, dose or an alternative could help. Cleveland Clinic notes management sometimes focuses on masking the taste when the medicine must continue.

Cleveland Clinic describes the usual work-up: a review of medicines and symptoms, a mouth and nose exam, smell identification tests (because smell loss often masquerades as a taste problem), taste threshold tests, and blood tests such as a complete blood count and levels of iron, vitamin B12, calcium and potassium. Imaging is used if a structural cause is suspected. Zinc and vitamin B deficiencies are among the causes it lists. The NIDCD notes an ear, nose and throat specialist (otolaryngologist) usually diagnoses taste disorders.