A bitter taste in the mouth can occur for many reasons, ranging from acute problems (like poor oral hygiene) to more serious problems (like hepatitis or acid reflux).
Smoking cigarettes can also cause a bitter taste in the mouth, which can persist for a few minutes to a few hours. This typically improves after eating other foods, drinking water, or brushing your teeth.
If you notice that you have a bitter taste in your mouth frequently, or if it persists with no improvement, you should consult a general practitioner or a gastroenterologist is recommended to assess whether the symptom is due to a medical condition.
The most common causes of a bitter taste in the mouth include:
1. Poor oral hygiene
This is the most common cause for a bitter taste in the mouth, especially if it occurs after waking up. A build-up of saliva and bacteria on the tongue, teeth, and gums can lead to bad breath and changes in taste perception.
How to treat: Brush your teeth at least twice a day, once after waking-up and again before going to sleep. It is also very important to brush the tongue to prevent coated tongue, which is a build-up of bacteria and dead cells that can also contribute to foul breath.
2. Antibiotics or antidepressants
There are some drugs that, when ingested, are absorbed in the body and then released in the saliva, causing a bitter taste in the mouth. Some examples include antibiotics (e.g. tetracyclines), gout medication (e.g. allopurinol), and lithium. Some drugs used to treat heart disease can also cause a bitter taste.
People who use antidepressants may experience a dry mouth, which can also alter taste perception.
How to treat: The bitter taste usually resolves within a few days of taking a new medication. However, if it is constant and unpleasant, notify your prescriber, who may suggest an alternative medication for you.
Dysgeusia, a change to taste perception, is a very common symptom for many women during the first trimester of pregnancy. It arises due to hormonal changes and usually resolves within a few days.
Some pregnant women may report a taste similar to having a coin in their mouth or drinking water from a metal cup, for example. Learn more about other pregnancy symptoms that can emerge early on.
How to treat: An effective way of getting rid of the bitter taste in the mouth is to drink lemonade or suck on a lemon popsicle.
4. Vitamin supplements
Some vitamin supplements that contain high amounts of metallic substances, such as zinc, copper, iron, or chromium, can cause a metallic and bitter taste in the mouth. This side effect is very common and usually appears once the supplement is completely absorbed in the body.
How to treat: It is recommended to wait a few minutes to allow the body to fully absorb the supplement. If the bitter taste is very intense or persists, you should discuss the possibility of changing your dose or using an alternative supplement with your prescriber.
5. Gastroesophageal reflux disease (GERD)
GERD happens when stomach content backs-up into the esophagus during digestion. The acid can flow back up to the mouth, leaving a bitter taste.
How to treat: Avoid eating foods that are very fatty or difficult to digest, as they increase the acidic content in the stomach. It’s also important to avoid eating very large meals, as they make it difficult for the stomach to digest efficiently. Read more about the GERD diet and how to start incorporating it into your lifestyle.
6. Hepatitis, fatty liver or cirrhosis
When the liver is not working properly, the body begins to accumulate high amounts of ammonia, which is a toxic substance normally transformed into urea by the liver and eliminated in the urine. Increased levels of ammonia cause a change in taste, similar to fish or onion.
If you suspect your bitter taste is related to a liver problem, report your symptoms in our liver disease symptom checker and assess your risk.
How to treat: Liver problems usually present with other symptoms, like fatigue or general malaise. Therefore, if liver disease is suspected, it is recommended you seek the medical opinion of a gastroenterologist, who can confirm a diagnosis and start treatment if necessary.
7. Cold, sinusitis and other infections
Bacterial infections in the upper respiratory tract (e.g. colds, rhinitis, sinusitis or tonsillitis) can cause a bitter taste in the mouth due to by-products produced by the bacteria.
How to treat: It is important to drink at least 2L (about 8 cups) of water per day, as this helps to both relieve the bitter taste and speed-up recovery. However, it is also recommended to consult a general practitioner to confirm any diagnosis and start treatment as indicated.
8. Diabetic ketoacidosis
Diabetic ketoacidosis (DKA) is a complication of diabetes that is characterized by a high level of sugar in the blood with a low level of sugar within the cells. The body tries to compensate this by producing more ketones to ensure there it has enough energy for regular functioning.
Due to a high amount of ketones circulating in the blood, pH levels decrease. This cause symptoms like a bitter taste, bad breath, dry mouth and confusion.
How to treat: Blood sugars should be regularly assessed by diabetics, and levels that are 3 times above normal should be urgently assessed, as this may be a sign of DKA.
Treatment in the hospital includes continuous monitoring and IV insulin to maintain hydration and reduce blood sugar.
9. Burning mouth syndrome
Burning mouth syndrome is a chronic condition caused by constant pain and burning in the oral cavity. It is associated with symptoms like a bitter or metallic taste, dry mouth and reduced saliva.
This syndrome commonly affects menopausal or post-menopausal women, but it may also emerge as a result of other health conditions, such as am infection (fungal, viral or bacterial), salivary gland problem, mouth sores, diabetes, hormonal disorders and nutritional deficiencies.
How to treat: If you suspect burning mouth syndrome, you should consult a doctor for a full evaluation and to identify the underlying cause. If related to another health condition, the burning mouth and bitter taste will usually resolve once the causative illness is corrected.
Treatment for burning mouth syndrome that is unrelated to another health condition is usually aimed at relieving active symptoms. The doctor may prescribe benzodiazepines (like clonazepam), lipoic acid supplements, capsaicin, anticonvulsants or tricyclic antidepressants.
10. Chemotherapy or radiation therapy
Some medications used for chemotherapy can damage taste buds and cause changes to taste. Many chemo patients report a bitter or metallic taste in their mouth.
Radiation therapy used to treat head and neck cancers can also damage taste buds, as these are sensitive to radiation. Other related symptoms include dry mouth, sore mouth, and sore throat, all which can worsen the bitter taste in the mouth.
How to treat: A bitter taste in the mouth generally improves 3 to 4 weeks after the last treatment. However, you can consider measures to prevent worsening, like chewing gum, sucking on hard candy, avoiding canned foods, seasoning foods with natural herbs, keeping your mouth clean and eating food at room temperature.
You can also perform a sodium bicarbonate, salt and water gargle to help improve the taste of food. Mix one teaspoon of salt and one teaspoon of sodium bicarbonate in 4 cups of water.
11. Pine mouth
Pine mouth is a condition that some people may experience after eating pine nuts. It is characterized by a bitter taste in the mouth and discomfort, which can appear 1 to 3 days (and up to 2 weeks) after eating pine nuts. The cause of this condition is unknown.
How to treat: Treatment is not necessary for pine mouth, as the bitter taste usually resolves on its own within a few days.