Oral Thrush During Chemotherapy

Symptoms, Complications, and Treatments

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sticking tongue out

Oral thrush is a type of yeast infection that's triggered by the Candida albicans fungus. It causes white spots on the inside of the mouth and/or tongue. 

If you've developed oral thrush during chemotherapy—or if you've heard that it could happen—you may be wondering what the symptoms are or how it is treated. Thankfully, oncologists are very familiar with treating this common side effect of chemotherapy, which is often called "chemo thrush."


Oral thrush is more likely to occur in people who are undergoing chemotherapy, especially in those who are prescribed steroids that suppress the immune system. Candida albicans is found naturally in small amounts in the body, but overgrowth can occur when the immune system is suppressed or when antibiotic treatment gets rid of the "good bacteria" that normally inhabit the mouth. Chemotherapy attacks rapidly dividing cells, such as the mucous membranes in the mouth, and that also raises the risk for oral thrush. Other risk factors include high blood sugar and poorly fitting dentures.


Symptoms that suggest that you may have thrush include:

  • White, creamy patches or lesions on the tongue or on the inside of the mouth. (Some people describe it as looking like cottage cheese or yogurt that is spread on the inside of the cheeks, tongue, or back of the throat.)
  • A burning sensation inside the mouth or throat. 


    In addition to being painful on its own, oral thrush can lead to further complications including:

    • Dehydration and malnutrition due to discomfort with eating and drinking
    • Secondary bacterial infections, which can develop in areas that are already damaged by the fungus
    • Changes in a person's sense of taste, in addition to the taste changes that are associated with chemotherapy (the notorious metal mouth)


      Treatment for oral thrush usually involves a combination of a medication and another type of therapy. 

      The most common medications used include:

      • Mycelex (clotrimazole): This is a topical drug that is prescribed as a lozenge, which is also called a troche. As the lozenge slowly dissolves in the mouth, the medicine is absorbed into the bloodstream. Each lozenge generally takes about 20 to 30 minutes to dissolve and is usually taken five times a day.
      • Nystatin: This drug is also commonly prescribed in a troche or liquid form. With liquid nystatin, you swish and swallow the medication. Some people report that nystatin tastes bitter or acidic, but ask your pharmacist if he or she can add flavoring to it. Mint flavoring is a popular recommendation as it works well to mask the bitterness.
      • Diflucan (fluconazole): This is another medication that's used to treat thrush. For people who are undergoing chemotherapy, it is most often prescribed in a tablet form. Common side effects of Diflucan include headaches, nausea, and dizziness. But, these side effects are generally very mild. In some cases, Diflucan may be prescribed to prevent thrush in people who are undergoing cancer treatment. While Diflucan is an excellent drug for treating oral thrush, it can be expensive for those who do not have health insurance or have maxed out on their prescription drug plan. There is a generic option available, so be sure to ask your doctor before he or she writes the prescription. If you are paying out of pocket, be sure to shop around before filling the prescription. Some patients have found certain pharmacies to be considerably less expensive than others. Some dental insurance plans will also pay for Diflucan.

        Doctors may also prescribe a mouthwash that is a combination of several medications. It is often referred to as "Magic Mouthwash" or "Mary's Magic Mouthwash" and it consists of a mixture of a few different drugs. It treats the oral thrush and relieves the discomfort that's caused by the infection.

        It is important to note that Magic Mouthwash and Mary's Magic Mouthwash are not brand names but nicknames for the formula. There are several different formulas and it is at a doctor's discretion to determine which drugs to include and the appropriate dosage.

        With a quick online search, you can learn the formula for this mouthwash.

        But please do not attempt to make it at home. It's best to leave that work to a pharmacist. Magic Mouthwash may also be prescribed to treat the dreaded chemotherapy-induced mouth sores.

        It is important to finish the medication that you are prescribed, even if your symptoms improve or go away. 

        Lifestyle Tips

        Some people find relief from the burning and itching sensation that's caused by thrush by eating and drinking cold foods and drinks. Popsicles, ice cream, smoothies, and crushed-ice beverages can temporarily help the burning sensation. Chilled soups make for excellent snacks or side dishes.

        If you have oral thrush, use a soft toothbrush until the infection clears. Avoid alcohol-based mouthwashes as they may exacerbate the burning sensation. Thankfully, oral thrush isn't one of the long-term side effects of chemotherapy and usually disappears (with treatment) shortly after chemotherapy is finished.

        A Word From Verywell

        If your loved one is dealing with oral thrush (or other side effects of cancer treatment), check out these tips on cancer support. Don't let the condition breed more challenging moments between you two.


        National Cancer Institute. Oral Complications of Chemotherapy and Head/Neck Radiation—Patient Version (PDQ). 1/22/16.