Caphosol for Prevention and Treatment of Mouth Sores

A Treatment for Mucositis During Cancer Chemotherapy and Radiation

Chemotherapy and radiation can cause mouth sores (mucositis). Caphosol is sometimes recommended as a mouth rinse during chemotherapy for cancers such as breast cancer or radiation therapy for cancers around the head and neck.

Caphosol is a calcium phosphate solution that resembles saliva. It works by lubricating your oral tissues (mucosa) and soaking into any mouth sores, reducing inflammation and encouraging healing.

While recent studies have questioned the effectiveness of Caphosol in alleviating the discomfort of mouth sores relative to other treatment options, many patients and oncologists believe it offers some relief.

This article discusses using Caphosol for mouth sores during cancer treatment, its effectiveness, and its side effects. Other tips for coping with mouth sores are also discussed.

Young woman rinsing mouth, leaning over sink, close-up
Christopher Robbins / Getty Images

Caphosol Use for Cancer

Mouth sores can occur during different types of cancer treatment, including chemotherapy, radiation therapy to areas near the mouth, and some targeted therapies.


Mucositis, or mouth sores, is a common side effect of chemotherapy. It occurs in 20%–40% of patients within the first two weeks of chemotherapy. Mouth sores occur when chemotherapy drugs attack the rapidly dividing cells of the mucous membranes lining your mouth.

Mouth sores may occur on your mouth and tongue (oral mucositis), and further down your digestive tract in your esophagus and intestines. These sores can be painful and often limit the foods you can eat.

Most of the time, mouth sores are more of a nuisance than a problem. But when they are severe, they can limit your eating and lead to poor nutrition when you need the best nutrition possible. This may be amplified if you have also developed taste changes due to chemotherapy.

Sometimes, mouth sores can become secondarily infected with either bacteria or yeast (oral thrush). If this occurs, your oncologist will likely prescribe an antibiotic or antifungal medication.

Radiation Therapy

Radiation therapy to the head and neck, especially when combined with chemotherapy, can also lead to problematic mouth sores. In contrast to chemotherapy, these sores can persist for some time after treatment has been completed. Measures such as sucking on ice chips are often ineffective in preventing the sores.

Mucositis occurs around the third week in about 90% of people receiving radiation for head and neck cancer. The pain can be severe and may limit treatment tolerance.

Bone Marrow Transplant

Mouth sores that develop following a bone marrow transplant require special attention, as it's important to distinguish mouth sores related to treatment from symptoms of graft-versus-host disease. If you've had a bone marrow or stem cell transplant it's important to talk to your oncologist before you try any type of mouth sore treatment.


Studies looking at the effect of Caphosol on the prevention and treatment of mouth sores during chemotherapy have been mixed. It appears to work better with the type of chemotherapy used for breast cancer than with the high-dose chemotherapy and stem cell transplants used for blood-related cancers.

A 2019 study compared the use of Caphosol with standard topical therapy regarding both pain control and healing. It was found that Caphosol did not demonstrate any benefits superior to standard therapy.

A 2017 study looking at the use of Caphosol in people undergoing radiation therapy for head and neck cancer revealed similar findings, with no reduction in the incidence or duration of mouth sores in people who used Caphosol.

Regardless of the data, some people may benefit from Caphosol. It's important to talk to your oncologist about recommendations for your situation.

Using Caphosol for Mouth Sores

If Caphosol has been recommended, it's helpful to know how it works and how to properly use the solution. Do not swallow Caphosol.

Caphosol comes in a box of 30 doses and is available to use at home. The doses are packed as two different solutions, Caphosol A and Caphosol B. You will mix these immediately before using the solution as a mouth rinse. This product should be kept at room temperature.

How to Use Caphosol

Follow these steps to use Caphosol most effectively:

  • Plan the timing of your dose so that you will not be eating or drinking anything for at least 15 minutes after you use Caphosol. This helps prevent dilution of the solution and gives it time to soak into dry mouth tissues.
  • Separate one blue container (Caphosol A) and one clear container (Caphosol B) from those in the pack of 30 doses.
  • Remove the caps from the blue and clear containers, and empty the contents together into a clean glass.
  • Do not add water or any other fluid.
  • Swirl the glass of Caphosol around gently to mix the two solutions.
  • Immediately after mixing, use Caphosol as a mouth rinse.
  • Pour half of the solution into your mouth, then swish and gargle with it for one full minute.
  • Spit out the solution.
  • Repeat your swish and gargle with the second half.
  • Again, do not swallow Caphosol, but spit it out.
  • Do not eat or drink for the next 15 minutes.
  • Use Caphosol four times a day for relief of mucositis.

Side Effects and Precautions

Unlike the majority of treatments used for cancer, research and testing have found no notable side effects of Caphosol. There are no notable interactions of Caphosol with other drugs or oral products.


Caphosol works best if you use it according to the instructions on the package. This includes:

  • Not eating or drinking for 15 minutes after using Caphosol solution.
  • Talking to your healthcare provider about using a smaller dose of Caphosol if you are on a low-sodium diet.
  • Letting your healthcare provider know if your mucositis increases or the pain from mouth sores or dry tissues continues. Your oncologist may sometimes recommend using a higher dose or more frequent doses of Caphosol.
  • Keeping this and all other medications out of the reach of children.

Coping With Mouth Sores

In addition to using mouth rinses as recommended by your oncologist, there are many things you can do yourself to cope with annoying mouth sores, including:

  • Avoid spicy foods.
  • Avoid citrus foods, such as orange juice and tomato juice, which can significantly increase pain.
  • Avoid salty foods.
  • Avoid sharp foods, such as crackers, corn chips, and toast
  • Drink fluids and sometimes soups through a straw, which can keep the food away from painful mouth sores.


Caphosol is artificial saliva with few side effects. Studies about its effectiveness in treating cancer-related mouth sores have been mixed. However, it may be worth trying if approved by your healthcare provider. Many people report that it can help moisturize the mouth and help with healing.

A Word From Verywell

Mouth sores are not only uncomfortable during cancer treatment but can interfere with your ability to eat and get the nutrition you need. Some reports say that Caphosol reduces the pain associated with mouth sores without any significant side effects or interactions, while other studies have found the solution offers no benefit over standard solutions. With any type of treatment, it's important to talk to your oncologist first.

Frequently Asked Questions

  • Do you need a prescription for Caphosol?

    Caphosol does not require a prescription. You can purchase it over the counter. However, be sure to let your healthcare team know about this and any other over-the-counter products you are using.

  • Where can you buy Caphosol?

    Caphosol can be purchased at any drugstore or pharmacy without a prescription. However, not all stores carry it, so consider doing an online search or calling ahead to be sure it is in stock.

  • What happens if you swallow Caphosol?

    Caphosol should only be used as an oral rinse and then spit out. According to the package, no adverse effects are expected if you accidentally swallow some. However, if you experience a reaction, contact your local poison control or seek medical attention.

  • How long does Caphosol last?

    Caphosol will last for different amounts of time depending on the cause and severity of their mouth sores. Use two to 10 times per day or as instructed by your healthcare provider.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Kiprian D, Jarzabski A, Kawecki A. Evaluation of efficacy of Caphosol in prevention and alleviation of acute side effects in patients treated with radiotherapy for head and neck cancers. Contemp Oncol (Pozn). 2016;20(5):389-393. doi:10.5114/wo.2016.64600

  2. Oncology Nursing Society. Calcium phosphate mouth rinse/Caphosol.

  3. Wong KH, Kuciejewska A, Sharabiani MTA, et al. A randomised controlled trial of Caphosol mouthwash in management of radiation-induced mucositis in head and neck cancer. Radiother Oncol. 2017;122(2):207-211. doi:10.1016/j.radonc.2016.06.015

  4. Brown TJ, Gupta A. Management of cancer therapy–associated oral mucositisJCO Oncology Practice. 2020;16(3):103-109. doi:10.1200/JOP.19.00652

  5. The Oral Cancer Foundation. Mucositis.

  6. Villafuerte-gutierrez P, Villalon L, Losa JE, Henriquez-camacho C. Treatment of febrile neutropenia and prophylaxis in hematologic malignancies: A critical review and update. Adv Hematol. 2019;2019:4120631. doi:10.1155/2014/986938

  7. American Cancer Society. Stem cell transplant side effects.

  8. Murdock JL, Reeves DJ. Chemotherapy-induced oral mucositis management: A retrospective analysis of MuGard, Caphosol, and standard supportive care measures. J Oncol Pharm Pract. 2020;26(3):521-528. doi:10.1177/1078155219850298

  9. Monthly Prescribing Reference. CAPHOSOL Rx.

  10. EUSA Pharma. Caphosol.

  11. American Cancer Society. Mouth sores or sore throat.

Additional Reading
Originally written by Pam Stephan
Pam Stephan is a breast cancer survivor.
Learn about our editorial process