Causes of a Sour or Bitter Taste in the Mouth

Having a bitter, sour, or foul taste in your mouth may be a reaction to something you ate. It's not uncommon to suddenly "burp up" something that didn't agree with you. However, this symptom can be worrisome if it happens frequently.

Three of the more common causes of a bad taste in the mouth are:

• Gastroesophageal reflux disease (GERD)
• Medications, including chemotherapy
• Zinc deficiency

Any change in the typical taste perception is known as dysgeusia. It is one of several conditions that affect the taste. Other taste disorders include hypogeusia (the loss of taste sensitivity) and ageusia (the complete loss of taste).

Finding the proper treatment can be a process of trial and error. In some cases, the condition may resolve on its own. Other times, it may require treatment to resolve the underlying cause.

This article explains the common causes of bitter taste in the mouth and how they are diagnosed and treated.

Medications

According to research published in the journal Canadian Family Physician, at least 250 different drugs can cause a bitter taste in the mouth. It's theorized that this occurs because of:

• How drugs impact the taste receptors in the brain
• The taste of medicines when mixed with saliva
• A phenomenon where a drug molecule circulating in a blood vessel of the tongue interacts with taste bud receptors

Some of the more common culprits include:

• Antibiotics: Including ampicillin, macrolides, quinolones, sulfamethoxazole, trimethoprim, tetracycline, and metronidazole
• Heart medications: Including many high blood pressure medications, diuretics, statins, and antiarrhythmics
• Chemotherapy drugs: Including cisplatin, cyclophosphamide, and etoposide
• Neurologic medications: Including antiparkinson drugs, migraine medications, and muscle relaxants
• Psychotropic drugs: Including most tricyclic antidepressants, some antipsychotics, anti-anxiety drugs, mood stabilizers, and hypnotics
• Other prescription and over-the-counter (OTC) drugs: Including thyroid drugs, antihistamines, bronchodilators, anti-inflammatories, smoking cessation aids, antifungals, and antivirals

Diagnosis and Treatment

Doctors typically diagnose drug-induced sour taste after excluding other things. Healthcare providers will often start by checking for:

• Infection
• Cancer
• Nutritional deficiencies
• Acid reflux

Based on the timing of the symptoms, your doctor may be able to pinpoint the drug causing the problem. They may even be able to decipher it after reviewing other medications you are taking. Then, if appropriate, the offending drug might need to be stopped or substituted.

In some cases, taking a dose at night instead of during the day may help reduce the bitter taste in your mouth. However, if it is related to a drug you're using for a short period, such as an antibiotic, you may need to bear with the unpleasant taste until treatment is complete.

Never stop taking a medication before speaking with your healthcare provider. Instead, work with your doctor to determine if a medication is causing your bitter taste. They will help you identify what may be to blame and, if possible, change the drug or alter the dose.

Zinc Deficiency

Zinc deficiency is one of the more common causes of taste disturbances. The sour taste associated with zinc deficiency is often difficult to describe. Some use terms such as "strange," "off," or simply "bad."

A zinc deficiency may be caused by:

• Lack of zinc in a diet
• Poor absorption of zinc in the intestines
• Alcohol
• Chemotherapy
• Thiazide diuretics, drugs that increase urine output
• Capoten (captopril), an ACE inhibitor used for high blood pressure and other issues
• Cuprimine (penicillamine), used to treat kidney stones
• Malnutrition
  

In addition, zinc deficiency is associated with certain diseases. They include:

• Cancer
• Celiac disease
• Chronic kidney disease
• Crohn's disease
• Diabetes
• Liver disease
• Pancreatitis
• Sickle cell disease
• Ulcerative colitis
  

Diagnosis and Treatment

Doctors diagnose zinc deficiency by measuring the concentration of zinc in a sample of blood.

If you are low, your doctor may suggest that you increase zinc in your diet. Foods naturally high in zinc include:

• Shellfish
• Red meat
• Beans and legumes
• Eggs
• Dairy

While a daily zinc supplement may help normalize blood levels, it won't resolve what caused low levels in the first place.

For a long-term resolution, however, it's essential to identify the cause. For example, if a medication causes a zinc deficiency, you may need to work with your doctor to stop, substitute, or adjust the dose of the offending drug.

Figuring this out is often a process of trial and error. Your doctor will consider your age, weight, medical history, health status, current drug use, and co-occurring symptoms as they evaluate potential causes.

While you can often resolve zinc deficiency by taking supplements, it's a good idea to find out why your body is low on zinc. Learning the cause will allow you to resolve the problem long-term.

GERD

The lower esophageal sphincter (LES) sits at the bottom of the esophagus. These group of involuntary muscles contract to keep the acid in your stomach from coming back into your throat.

Usually, the LES functions as a one-way valve. However, with gastrointestinal reflux disease (GERD), it suddenly relaxes. This causes the LES to open when it shouldn't, allowing stomach acid to flow back into the esophagus.

Known as acid reflux, this can cause a sour or bitter taste, as well as:

• Heartburn
• Chest pain
• Bad breath
• Burning in the throat
• Difficulty swallowing
• The sensation of a lump in the throat
• Coughing
• Hoarseness

You can usually pinpoint GERD as the cause of a sour or bitter taste if it co-occurs with heartburn and develops soon after eating. Still, see your healthcare provider for an evaluation and formal diagnosis.

Pregnancy and obesity can also contribute to GERD. That's because, in both situations, excess weight places stress on the stomach and esophagus.

A hiatal hernia (stomach hernia) can have a similar effect. This occurs when part of your stomach pushes through your diaphragm. As the stomach pressed upward, it can change the position of the LES so that it has trouble staying shut.

Diagnosis and Treatment

To diagnose GERD, your doctor may suggest the following:

• Endoscopy, a procedure that allows for examination of the LES
• Manometry, a test that measures the contractions of the esophageal muscles
• Ambulatory pH probe in which a swallowed probe measures how and when reflux occurs

Treatment typically involves a combination of OTC and prescription medications. These include:

• Antacids
• H2 blockers like Prilosec (omeprazole)
• Proton pump inhibitors (PPIs) like Nexium (esomeprazole)
• Lioresal (baclofen) to help strengthen the LES muscles

Changes in diet, weight loss, and quitting smoking can also help.

It may take some time to identify which foods or activities trigger your acid reflux. Therefore, sometimes effectively treating GERD requires limiting or avoiding certain foods and taking OTC or prescription medications. The good news is that once you control GERD symptoms, the sour or bitter taste sensations should also go away.

Other Causes

Other conditions may change your taste perception or make an existing disorder more pronounced. These include:

• Cigarette smoking, which dulls the taste and makes food less palatable
• Xerostomia (dry mouth syndrome), which alters taste perception
• Dehydration, which leads to a dry mouth and affects the taste
• Anxiety and stress, which can lead to a dry mouth and change the way things taste
• Infection or illness
• Oral candidiasis (thrush), a yeast infection in the mouth/throat
• Poor dental hygiene
• Pregnancy, especially during the first trimester
• Menopause, which may alter taste due to changes in hormone levels
• Brain injury or surgery, which can trigger phantom taste sensations
• Neurologic (nerve-related) disorders such as epilepsy, multiple sclerosis, Bell's palsy, brain tumors, and dementia
• Radiation therapy of the head and neck, which can damage salivary tissues
• Lead poisoning, often recognized by a characteristic blue line along the gums
• Pine nut syndrome, which can cause a bitter taste that may occur one to three days after eating pine nuts
• Burning mouth syndrome, which can also cause a burning or scalding sensation in the mouth

Coping

Whatever the underlying cause of bitter taste, you can do things to help reduce the symptoms. Some practical home remedy tips include:

• Drink plenty of water, which can hydrate your mouth and cause you to urinate. Frequent urination can help flush out impurities that may be contributing to your symptoms. Adding a little lemon juice to your water may also help reduce the bad taste in your mouth.
• Chew sugar-free gum to increase saliva production.
• Practice good oral hygiene, including getting regular dental checkups and using an antibacterial mouthwash.
• Rinse your mouth with a half-teaspoon of salt plus a teaspoon of baking soda added to a glass of water, which may help reduce the bitter taste.
• Avoid spicy or fatty foods, which promote acid reflux. Even if GERD is not the cause of the bad taste in your mouth, the reflux of stomach acid will only worsen your symptoms.
• Stop smoking. Whatever the underlying cause of sour taste, smoking will only amplify the effects.

Summary

Dysgeusia is the medical term for a change in the usual taste perception. Often this disorder is associated with a bitter or sour taste in the mouth.

Many things can cause a bitter taste in the mouth, including medications, nutritional deficiencies, GERD, other health conditions that lead to a dry mouth.

Treatment depends on the cause, but you can address symptoms in the short term by drinking lots of water, maintaining good oral hygiene, and quitting smoking.