It's not something that you should ignore.

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We've probably all had the experience of tasting blood in our mouth. Whether you've bitten your cheek or tongue, cut the inside of your mouth with your braces, or flossed your teeth a little too aggressively, that distinct metallic taste has likely filled your mouth. But have you ever had the disconcerting experience of tasting that iron flavor in your mouth when you hadn't accidentally injured yourself? 

One TikTok user recently posted a video about tasting blood while running. That might even be something that you yourself have experienced because, yes, engaging in a high-intensity workout can be a reason why you start having that metallic taste. But it's not the only thing that can lead to the taste. Here are some reasons why you might have a blood or metallic taste in your mouth—and whether or not it should be a concern.

Reasons Why You Taste Blood , portrait of young beautiful dark-skinned woman with sour grimace
Credit: Getty Images

Exercise

In the TikTok video, a woman can be seen slowing down on her run and moving her mouth as if to taste something, writing that she tastes blood. Someone who identified himself as an emergency physician then cuts in to explain why that happens. A lot of things on TikTok are sus, but according to Lisa Lewis, MD, a clinician practicing in Fort Worth, Texas, there is truth to this video. "This is felt to be related to the breakdown of red blood cells which subsequently release minute amounts of iron in the lungs," she tells Health. "If a person is working out and breathing heavily, irritated areas in the mouth, nose, or throat may also cause a metallic taste in the mouth." Dr. Lewis adds that this is most common in areas with drier and cooler weather.

The runner in the TikTok video hinted it was because she was out of shape that she tasted blood. While that's not necessarily true, Dr. Lewis does recommend stopping to rest, as well as seeing if there's actually visible blood in your mouth. If there is actual blood or the taste persists, it's best to check in with your doctor.

COVID-19

A loss of sense of taste was one of the first widely reported symptoms of COVID-19 when the pandemic first started. But it's not just the absence of taste that the disease might cause. "It has been reported that some individuals infected with COVID-19 experience the symptom of a metallic taste in their mouth," New York City-based internist Nesochi Okeke-Igbokwe, MD, tells Health. For example, doctors in Philadelphia wrote about the case of a 59-year-old woman who said that the foods she normally enjoyed tasted "bland and metallic" after contracting COVID-19.

Exactly why some people have experienced that symptom is still not totally understood, with Dr. Okeke-Igbokwe saying that "the pathogenesis of this symptom in those with COVID-19 continues to be investigated." The good news, Dr. Lewis says that the ongoing research indicates that this is not a permanent phenomenon. In the case of the woman that Philadelphia doctors reported on, the metallic taste went away about two weeks after it first cropped up.

It's not just a virus like COVID-19 that can cause this experience, either. Dr. Lewis explains that bacterial infections can also be the culprit when you taste blood in your mouth. Fortunately, this will also be resolved when you properly treat the infection.

Medications and supplements

Have you recently started a new medication? Or perhaps you've added additional supplements or vitamins to your regimen? Well if you're tasting blood, there's a chance that one of those meds could be responsible for that bloody flavor on your tongue and lips. "Medications that may have a blood taste side effect include antibiotics, antidepressants, and blood pressure and diabetes medications," Dr. Lewis says. "Multivitamins, especially those with heavy metals or iron may cause a blood taste side effect."

Fortunately, if the unpleasant taste does stem from your meds, it probably isn't any cause for concern and may even abate in time. If it persists, the taste may be due to something else and should be discussed with your healthcare professional, per Dr. Lewis.

Allergies

If you're someone with allergies, you know how disruptive and irritating they can be. They turn beautiful spring days into a tissue fest or make snuggle time with your pet an itchy, eye-watering affair. They can also wreak havoc in your mouth. "Allergies are a common reason for taste changes, especially a metallic taste in the mouth," Dr. Lewis says. "In addition to the increased secretions in the respiratory passages, medications associated with allergies (such as antihistamines) may cause a metallic taste and dry sensation in the mouth."

Pine Nut Syndrome

This one is super specific. It's not too common, but it does happen to some people who eat pine nuts. "There have been past case reports of individuals experiencing a metallic taste in their mouth for some days post-pine nut ingestion," says Dr. Okeke-Igbokwe. "The altered taste in the mouth appears to be short-lived, and it is unclear why this phenomenon may even happen to a select few."

Someone who develops pine nut syndrome will generally start having a bitter metallic taste 12 to 48 hours after they've eaten pine nuts, according to the National Institutes of Health (NIH). That taste is usually amplified when eating other food and lasts two to four weeks. "Recent findings have correlated this disorder with the consumption of nuts of the species Pinus armandii, but no potential triggers or common underlying medical causes have been identified in individuals affected by this syndrome," according to NIH researchers. 

Pregnancy

Few things can cause major changes to your body like pregnancy can, which can have an impact on everything from your appetite to the frequency of your restroom visits. And if you've been pregnant, you probably know that the experience can mess with your senses as well. "Pregnancy is one of the more common causes of a metallic taste in the mouth, and it is likely due to the hormonal fluctuations that arise during this period of time," says Dr. Okeke-Igbokwe. While some pregnancy-induced changes can be permanent, Dr. Lewis says that, fortunately, this one typically resolves itself.

Poor dental hygiene

The American Dental Association recommends that people brush their teeth for two minutes twice a day with a toothbrush that has soft bristles. Sure, you might slack on that from time to time. But maintaining good oral hygiene is of the utmost importance, as neglecting it can have consequences like bad breath, cavities, and even the taste of blood in your mouth. 

"If a person does not brush their teeth regularly, they may acquire inflammation or shrinkage of the gum tissue called gingivitis or periodontitis," Dr. Lewis says. "Because of the altered anatomy of the oral tissue with these conditions, a metallic taste in the mouth may be a result." 

Neurological conditions

Many of the reasons you may taste blood in your mouth are not a cause for concern or are treatable. However, some of the reasons are a bit more serious. "Altered taste, often referred to as a metallic taste, is associated with neurological conditions such as Bell's palsy (facial paralysis thought to be caused by a viral infection) and dementia," Dr. Lewis says. "A metallic taste associated with neurological illness is a result of weak signals from the underlying brain malfunction."

As for when you might experience the onset of this symptom? "Although there have been uncommon case reports of a metallic or blood taste in the mouth as the first sign of neurological disease, an alteration of taste is typically noted in combination with other neurological symptoms," Dr. Lewis says. So if you taste blood, don't automatically assume you have a neurological condition.

Should you go to the doctor if you're tasting blood?

Don't just ignore the taste of blood in your mouth—even if you don't think the underlying cause is serious. Dr. Lewis strongly encourages you to talk to your doctor if you taste blood, especially if you aren't exactly sure why you are experiencing the change.

Most times, the underlying cause of such a taste isn't serious. However, "some people unfortunately have serious illness or multiorgan medical conditions which may cause a metallic taste in the mouth," Dr. Lewis says. Diabetes—especially with hypoglycemia (low blood sugar)—is one example of a disease that can have the effect, according to Dr. Lewis. "If a person with diabetes notices this symptom, they should check their blood sugar promptly and treat as advised by their doctor," she explains. Chemical exposure may also cause the taste disturbance, according to Dr. Lewis, which would be something else a doctor should check out. But if you do have a metallic taste in your mouth because of one of these more serious reasons, "other symptoms will likely be present and obvious," Dr. Lewis says. Even if you continue to experience the taste alone, she suggests "it's best to have a medical evaluation to ensure there's no significant health problems that need to be addressed."

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