You might experience an unpleasant bitter taste in your mouth for various reasons.
A bitter taste could indicate an oral hygiene issue, such as gingivitis, or another condition may be altering your sense of taste (medically known as dysgeusia).
COVID-19, medication side effects, hormonal changes (brought on by pregnancy or menopause), acid reflux, and certain cancer therapies are among the many possible causes of changes to the sense of taste or smell.¹ ² ³
However, in some cases, a persistent bitter or metallic taste could also indicate a liver infection or liver disease.
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Your liver has many crucial functions, including removing toxins from your bloodstream.
In the advanced stages of liver disease (cirrhosis), your sense of taste can become distorted or diminished, which is sometimes reported as a bitter or metallic taste in the mouth.⁴ ⁵
Having a bitter taste in the mouth is also a symptom associated with acute viral hepatitis infection (which inflames the liver and can develop into liver disease).⁶
The exact cause of an altered sense of taste accompanying liver disease is not fully-established. Still, growing research indicates it may be connected with
Common side effects associated with liver disease medications⁷
Accumulation of toxins due to reduced liver function⁸
Neurological effects associated with liver failure⁹
Many things can cause dysgeusia, including
Brushing your teeth without being thorough could lead to a metallic taste in your mouth. That's because poor oral hygiene can lead to the development of gingivitis or cavities, which can cause a foul taste.¹⁰
A dry mouth (xerostomia) is a condition characterized by a lack of saliva. It can be caused by smoking, taking certain medications, or having a disorder like Sjögren’s syndrome.¹¹
Being pregnant causes physiological changes in almost all body systems. It has been established that the perception of taste changes during pregnancy, with possible dysgeusia.¹²
Estrogen levels affect oral health and saliva flow, and menopause can be accompanied by dry mouth or “burning mouth” syndrome, which could factor into changes to a changed sense of taste.¹³
The virus responsible for COVID-19, SARS-CoV-2, can readily infect the central nervous system, causing numerous symptoms and leading to Long COVID. An indication of infection and subsequent nerve damage is an altered sense of taste.¹⁴ ¹⁵ ¹⁶
Zinc deficiency is a well-known cause of taste alterations. Vitamin B12 deficiency also causes changes to taste, as well as tongue pain and inflammation (glossitis and glossodynia).¹⁷ ¹⁸
The kidneys are essential organs that remove waste from the body through urine. Dysgeusia, along with dysosmia (altered sense of smell), is common in chronic kidney disease, particularly in those undergoing dialysis. This is likely related to a build-up of toxins and their effects on the neural tissue.¹⁹
Some over-the-counter and prescription drugs can leave a metallic taste in your body. Examples of medications with this common side effect include (but are not necessarily limited to):²⁰ ²¹
Allopurinol (gout medicine)²²
Metformin (diabetes medication)
Antibiotics, including clarithromycin, metronidazole, and tetracycline
Blood pressure medications such as captopril
Paxlovid (nirmatrelvir & ritonavir) for COVID-19²³
Lithium (for treating psychiatric conditions)
Radiation therapy and chemotherapy can also leave a metallic or sour taste in the mouth. This is especially true for those with cancer that affects the neck or head.²⁴ ²⁵
Reflux or GERD occurs when stomach acid flows back into the tube connecting the stomach and mouth, causing a burning sensation. The acid may leave a bitter taste in your mouth.
Sense of taste is controlled by nerves in the head. Therefore, any condition or injury affecting the cranial nerves could cause a bitter taste in your mouth. For instance:
If a bitter taste in your mouth is caused by liver disease, it will only go away once the underlying liver problem is treated. Although cirrhosis is typically not curable, it can be managed. However, in the late stages, a liver transplant may be necessary.
You can help prevent or reduce a bitter taste by making several lifestyle changes:
Maintaining excellent oral hygiene like cleaning between the teeth daily, brushing teeth twice a day with fluoride toothpaste, gargling with mouthwash, brushing your tongue, and visiting the dentist regularly
Chewing gum that is sugar-free or contains xylitol (research shows it helps manage dry-mouth)²⁶
Avoiding smoking tobacco or using tobacco products
If a bitter taste in your mouth persists, don't hesitate to talk to your doctor so that they can perform a physical exam (or other forms of testing) and suggest appropriate treatment. Depending on their assessment, they may also refer you to an otolaryngologist (ear, nose, throat specialist), also known as an ENT. ENTs are qualified to diagnose and treat a taste disorder.
Can liver problems cause a bitter taste in the mouth? Yes, a bitter taste in your mouth can indicate liver problems. It can also indicate several other issues, such as kidney disease, dry mouth, and acid reflux. If you experience a metallic taste in your mouth, you should talk to your doctor for proper diagnosis and treatment. In the meantime, practice proper dental hygiene, stay hydrated, and avoid smoking (or develop a quit plan when you speak to your doctor).
Yes. Changes to the sense of taste are a common symptom of COVID-19. According to a 2022 study, an estimated 5% of adults go on to have lasting changes to their sense of taste or smell.²⁷
If you follow good oral hygiene, eat a nutritious diet, and make lifestyle changes like giving up tobacco, but nothing changes, see a doctor. Similarly, speak to your doctor if you are experiencing any of the above symptoms associated with liver disease, such as jaundice.
Yes. Some neurological conditions that affect the brain and nerves, such as Parkinson’s disease, can change sensory perception, including the sense of taste.
Dysgeusia | ENT Health
Acute hepatitis (2001)
Taste Disorders | National Institute of Dental and Craniofacial Research
Hyposmia and Dysgeusia in COVID-19 | Neurology Clinical Practice
Dysgeusia and Dysosmia in Chronic Kidney Disease: NHANES 2011-2014 | Journal of Renal Nutrition
Allopurinol | Arthritis and Rheumatology Clinics of Kansas
Taste changes | Canadian Cancer Society
Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy‐induced dry mouth - SHIP - 2007 - Journal of Oral Rehabilitation | Wiley Online Library