Sour Taste in Your Mouth? Here Are the 7 Most Common Causes

Pinpointing the culprit may suggest a solution
woman taking a drink of water to improve the taste in her mouth

Do you notice a sour taste in your mouth that bothers you between meals? Or is your appetite suffering because your food just doesn’t taste as good as usual? What the heck causes that?

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Family medicine physician Amber Tully, MD, discusses the seven most common reasons it might happen ― and when you can do something about it.

  1. Dehydration. In some cases, that sour taste could come from something as simple as not drinking enough water. “Dehydration can leave your mouth dry and can alter your sense of taste,” Dr. Tully says. What you can do: Make a point of drinking at least six to eight glasses of water each day to boost your hydration
  2. Smoking. Smoking is another common culprit. Not only is it the No. 1 cause of preventable disease and death. It also dulls your sense of taste, and may leave a sour or unpleasant taste in your mouth. What you can do: Add this side effect to your list of reasons to try to stop smoking.
  3. Not brushing and flossing properly. “Poor oral hygiene can often cause a sour taste in your mouth,” Dr. Tully says. “Poor oral hygiene can often cause a sour taste in your mouth,” Dr. Tully says. What you can do: Brush at least twice a day and floss at least once. And don’t skip those regular dental cleanings and check-ups, Dr. Tully advises.
  4. Infections or illness. When you get sick (with a cold or sinus infection, for example), your taste buds may feel the effects. When you get better, the sour taste should go away too. What you can do: Reduce your chances of picking up a bug or getting an infection by washing your hands often. Keep your hands away from your face (especially the mouth, nose and eyes). And, of course, avoid close contact with others who are sick.
  5. Medication and cancer treatment. Sometimes it’s not the infection or illness, but the medication you’re taking to treat it that leaves a bad taste in your mouth. Some antibiotics can cause a sour taste, Dr. Tully says. And it’s not just prescription medicines that have that effect. “Over-the-counter medicines such as antihistamines can cause the problem as well,” she says. “It also is sometimes a side effect of radiation therapy to the head or neck or chemotherapy to treat cancer.”
  6. Gastroesophageal reflux disease (GERD). If the muscle that opens and closes the opening between your esophagus and stomach doesn’t close completely after you eat, food and stomach acid can travel back into the esophagus. This is another common cause of a sour or unpleasant taste. What you can do: You can help manage GERD with diet and lifestyle changes, such as reducing meal size, not eating for several hours before bed and elevating your head when you lie down.
  7. Advancing age. Dr. Tully notes that advancing age is another possible culprit behind that sour taste in your mouth. “As we age our taste buds shrink and become less sensitive,” she says. “This can affect your sense of taste.”

You may find help for the sour taste through better hygiene or by addressing other causes such as GERD. But you may need your doctor’s help in pinpointing the cause.

“There are several reasons you may have a sour taste in your mouth,” says Dr. Tully. “In general, if you don’t have other symptoms it isn’t a cause for concern. But you should discuss it with your doctor.”

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