A Bitter Sensation in the Mouth: What Could Cause It?

The bitter taste sensation in your mouth is called "dysgeusia" and may be more than just a passing annoyance. Read on to find out what it is.

Reviewed and approved by the doctor Diego Pereira.

Written by Rafael Victorino Muñoz

Last update: 23 November, 2023

A persistent bitter sensation in the mouth is known by the medical term dysgeusia. It affects the perception of food flavors, preventing the enjoyment of a good meal or drink.

In general, this unpleasant sensation may be normal when consuming medications or foods that we aren’t used to. However, the fact that it becomes chronic or that we notice it when we eat sweets is a sign that something isn’t right. In this article, we’ll learn what dysgeusia is, what the possible causes are, and what we can do to eliminate it.

What is dysgeusia?

Our taste is a complex sense which involves several factors. There are about 10,000 taste buds in the mouth, each with 100 to 150 taste receptors. The chemical stimuli that create flavors are transmitted through the facial, glossopharyngeal, and vagus nerves. In part, tastes result from the interaction of what is perceived by both the taste buds and the sense of smell.

Dysgeusia, also called paragesuia, is a symptom that describes the unpleasant perception of tastes, according to studies. It usually manifests as a bitter sensation in the mouth, even when we’re not eating.

In most cases, this manifestation may be underestimated. However, research has shown that taste impairment can lead to a lack of pleasure in eating, food aversion, and malnutrition. Consequently, it can lead to decreased quality of life and muscle wasting.

Symptoms of dysgeusia

A bitter sensation in the mouth can occur in isolation or in association with other symptoms. It’s crucial to recognize these manifestations, as they facilitate medical diagnosis. Some of the symptoms that may accompany dysgeusia are the following:

• A burning sensation in the chest after eating, as in the case of people with gastritis.
• Trouble or difficulty swallowing a few mouthfuls, common in tonsillitis or pharyngitis.
• The sensation of dry mouth or xerostomia, caused by decreased saliva production. It should be noted that this symptom may be a result of dysgeusia or a trigger for dysgeusia.
• Bleeding and swollen gums, associated with periodontal disease.
• Bad breath or halitosis as the origin or cause of the bitter taste in the mouth.
• A loss of appetite, associated with an unpleasant perception of food.
• Decrease or loss of the sense of smell, since the changes of the sense of smell can lead to taste alterations.

7 possible causes of a bitter sensation in the mouth

Taste disorders are due to local, systemic or both causes, according to studies. Dysgeusia is associated with some diseases, drug intake, food, habits, and lifestyle.

Infections

Some infectious conditions can produce a bitter sensation in the mouth. In fact, recent studies indicate that dysgeusia is an early manifestation in patients with COVID-19. In this case, it’s related to the virus taking a liking for the nerve pathways, as well as damaging the taste buds and smell.

Similarly, research indicates a correlation of this symptom with other infectious conditions, such as influenza, tonsillitis, and sinusitis.

2. Gastroesophageal reflux disease

In this pathology, the upper sphincter of the stomach is affected, allowing acid to reach the esophagus. In addition to irritating, it causes a burning sensation in the throat, chest, and abdomen, as well as a bitter taste in the mouth and heartburn, according to studies.

3. Oral candidiasis

This is an infection produced by the fungus Candida albicans. It’s frequent in people with immunodeficiency. It causes whitish lesions on the tongue, inner cheeks, and throat. Research affirms that in pseudomembranous candidiasis, some patients may suffer from dysgeusia and a burning sensation in the mouth.

4. Neurological disorders

As already mentioned, in taste there are nerve connections that go from the taste buds to the brain. Therefore, various lesions and disorders in the nervous system can alter taste perception. This is observed in patients with brain tumors, Bell’s palsy, head trauma, brain surgery, strokes, and epilepsy, according to studies.

5. Sjögren’s Syndrome

This is an autoimmune disease characterized by a dry mouth and eyes. According to some research, decreased saliva production leads to burning in the mouth, difficulty chewing, pain when swallowing, and changes in taste perception.

6. Medications

Research has found that a wide variety of medications produce dysgeusia. This is due both to their bitter or metallic taste and to the fact that the compounds, in contact with saliva, produce this sensation. Among the drugs that can produce a bitter sensation in the mouth are the following:

• Antibiotics: tetracycline, ampicillin and metronidazole.
• Medications for heart failure and high blood pressure: antiarrhythmics, such as captopril and lisinopril. Likewise, statins and diuretics.
• Lithium-based drugs – for the treatment of bipolar disorder.
• Psychotropic drugs: antipsychotics, antidepressants, and anxiolytics.
• Drugs for neurological disorders: Such as those used in Parkinson’s disease, Alzheimer’s or migraines.
• Bronchodilators: used for the treatment of asthma and chronic obstructive pulmonary disease (COPD).
• Nonsteroidal anti-inflammatory drugs – such as ibuprofen, used for pain relief.
• Oral hypoglycemic agents: phenformin and glipizide.

Similarly, exposure to chemotherapy and radiotherapy is also associated with the perception of unpleasant tastes. A 2017 study, evaluated a total of 239 patients diagnosed with cancer and found that 64% of them developed dysgeusia during and after chemotherapy.

7. Other causes

Zinc deficiency is also one of the causes, among the most common, of taste disturbances, according to studies. This deficiency can be due to a lack of this mineral in the diet or to malabsorption, due to diseases such as celiac disease, Crohn’s disease, diabetes, or pancreatitis. It’s estimated that treatment with zinc supplements could be key in alleviating this symptom.

Both in pregnancy and menopause, due to hormonal changes, women may experience a bitter taste sensation in the mouth. Estrogen can alter the functioning of the taste buds.

Dental problems due to poor oral hygiene, cavities, gingivitis, and dental surgery cause dysgeusia. In addition, there are other causative factors, such as high levels of stress and lead contamination.

Dysgeusia treatment

Dysgeusia may resolve on its own without medical intervention. In other cases, treatment depends on identifying and resolving the cause.

If it’s a medication, the alternative is to discontinue or substitute another. It may also help to change the time of consumption. Similarly, if the dysgeusia is related to a dental problem or dental hygiene, you’ll need to take the necessary measures, and go and see an expert.

Recommendations to mitigate a bitter sensation in the mouth

There are several things you can do at home to alleviate the bitter taste sensation in the mouth. One is to maintain adequate hydration, as well as chewing gum (preferably sugar-free). This helps to increase saliva production.

Secondly, you should have good dental hygiene habits. From gentle brushing for two minutes, two to three times a day, through the use of dental floss, to antibacterial rinse if the dentist recommends it.

On the other hand, you should avoid excessive alcohol, caffeine, and certain spicy or fatty foods. Above all, quitting smoking is vital, since tobacco tar clogs the taste buds and alters their function.

A bitter taste in the mouth is almost always treatable

A bitter taste in the mouth is often a common problem, the causes of which can be treated. In most cases, the taste buds return to normal with no permanent effects.

A bad taste in the mouth shouldn’t be a cause for concern. However, it’s a sign that something is wrong, so seek help if it persists over time. If in doubt, consult your doctor.