Bitter Taste in Mouth: Causes

What causes a bitter taste in the mouth?

The taste process involves thousands of sensory neurons embedded in your taste buds and in the uppermost part of your nose (olfactory system). These neurons signal what you are eating and tasting to your brain. A bitter taste in the mouth can be caused by smoking, injuries, diseases or conditions that interfere with the taste process.

Bitter tastes may go away when the underlying condition, such as vomiting, is resolved. However, certain causes, such as chemical poisoning and autoimmune and neurological disorders, can be more serious or result in longer-lasting taste problems. If you are taking medications and suspect that they may be the cause of the bitter taste, talk with your doctor about your symptoms. It is possible that a switch to another medication may resolve the issue.

Common conditions that can cause a bitter taste in the mouth

Common conditions and everyday habits that can cause a bitter taste in your mouth include:

• Breathing through your mouth

• Dehydration

• Dry mouth

• Pregnancy

• Smoking

Diseases and disorders that can cause a bitter taste in the mouth

A bitter or altered sense of taste can be due to certain diseases, disorders and conditions including:

• Allergies and a stuffy nose

• Bell’s palsy (neurological disorder)

• Gingivitis (inflammation of the gums)

• Glossitis (inflammation of the tongue)

• Nasal polyps (sac-like, inflamed tissue growths)

• Salivary gland infection

• Sjogren’s syndrome (autoimmune disorder causing dry mouth and eyes)

• Upper respiratory infections, such as colds, sinusitis, strep throat, flu, or pharyngitis

• Vitamin B₁₂ or zinc deficiency

• Vomiting or regurgitation of stomach acid, which may be due to acid reflux or gastroesophageal reflux disease (GERD)

Trauma or injuries that can cause a bitter taste in the mouth

A bitter or altered sense of taste can arise from injuries and trauma including:

• Burning or biting the tongue

• Head, nose or mouth injuries

• Injuries to the sensory nerves that perceive taste

• Toxic exposure, such as ingestion of a toxic plant or chemical poisoning, such as exposure to insecticides

Other causes of a bitter taste in the mouth

A bitter or altered sense of taste can be caused by a variety of other conditions including:

• Dental or orthodontic appliances such as braces

• Dental surgery

• Radiation therapy to the head or neck

• Surgery to the ears, nose or throat

Medications that can cause a bitter taste in the mouth

A bitter or altered sense of taste can be due to many medications, especially if they are not swallowed quickly and begin to dissolve in the mouth or are chewed. Medications can include:

• Acetylcholine esterase inhibitors for Alzheimer’s disease

• Bronchodilators for asthma and COPD

• Captopril (Capoten) for high blood pressure and heart failure

• Certain antibiotics such as clarithromycin (Biaxin)

• Chemotherapy, such as Vinblastine (Velban), Vincristine (Oncovin, Vincasar), and Procarbazine (Matulane)

• Griseofulvin (Grifulvin V, Gris-PEG) for fungal skin infections

• Lithium (Eskalith, Lithobid)

• Penicillamine (Cuprimine, Depen) for severe rheumatoid arthritis and Wilson’s disease

• Rifampin (Rifadin, Rimacane) for tuberculosis or prevention of bacterial meningitis

• Thyroid medications

Questions for diagnosing the cause of a bitter taste in the mouth

To diagnose the underlying cause of a bitter taste, your doctor or licensed health care provider will ask you several questions about your symptoms. Giving complete answers to these questions will help your provider diagnose the cause of the bitter taste:

• Describe any changes in the texture, appearance and taste of the tongue. Have you had swelling, mouth sores, or lesions?

• Have you been in recent contact with any unusual substances or environments?

• Have you had any recent conditions of the mouth, throat or nose?

• List all the medications, supplements, and herbal drugs you are taking. Do you smoke?

• When did the bitter taste first appear?

What are the potential complications of a bitter taste in the mouth?

Complications associated with a bitter taste can be progressive, and vary depending on the underlying cause. Because a bitter taste can be due to a serious disease, failure to seek treatment can result in complications and permanent damage. It is important to visit your health care provider when you have a persistent change in taste or smell. Once the underlying cause is diagnosed, following the treatment plan outlined by your doctor can help reduce any potential complications including:

• Depression due to a reduced ability to enjoy food

• Loss of appetite and change of eating habits

• Malnutrition from loss of appetite

• Possibility of eating spoiled food due to the inability to taste spoiled food

• Weight loss