Managing Dry Mouth and Mouth Sores During Cancer Treatment

Some cancer treatments can affect healthy tissues as well as cancer cells.

Chemotherapy, for example, can affect rapidly dividing cells, including those lining the mouth.

Certain cancer medications may also contribute to changes in saliva production, immune function and tissue healing.

These effects can increase the likelihood of oral complications such as:

• Dry mouth

• Mouth sores

• Changes in taste

• Oral infections

• Gum sensitivity

• Difficulty swallowing

• Increased risk of dental decay

Not everyone undergoing cancer treatment will experience these problems.

The risk depends on the medications used, treatment intensity, oral health before treatment and other individual medical factors.

Understanding the cause of these symptoms is the first step toward managing them appropriately.

Dry mouth, medically known as xerostomia, refers to the sensation of having insufficient moisture in the mouth.

It may occur when saliva production decreases or when the composition of saliva changes.

Saliva is essential for oral health because it helps:

• Keep the mouth moist

• Support chewing and swallowing

• Wash away food particles

• Neutralise acids

• Protect teeth against decay

• Support normal oral tissues

When saliva is reduced, everyday activities such as speaking and eating may become uncomfortable.

Common Symptoms of Dry Mouth

Patients may experience:

• A dry or sticky sensation

• Thick or stringy saliva

• Difficulty swallowing dry foods

• Cracked lips

• Dryness of the tongue

• Changes in taste

• Bad breath

• Burning sensations

• Increased tooth sensitivity

Persistent dry mouth can also contribute to dental problems, especially when combined with changes in eating habits or difficulty maintaining oral hygiene.

Dry mouth during chemotherapy can have several contributing factors.

These may include:

Effects of Cancer Medications

Certain chemotherapy drugs and supportive medications can influence saliva production or oral moisture.

Dehydration

Nausea, vomiting, reduced fluid intake or other treatment-related symptoms may contribute to dehydration.

Changes in Eating and Drinking

Patients experiencing mouth discomfort or altered taste may drink less frequently.

Other Medications

Some medications used to manage pain, nausea, allergies or other conditions can contribute to mouth dryness.

Radiation Treatment

Radiation directed at the head and neck can damage salivary glands and cause significant dry mouth.

However, standard breast or chest-wall radiation does not usually expose the salivary glands to the same direct radiation effects.

The cause of dry mouth should be assessed in the context of the patient's specific treatment plan.

Managing dry mouth often involves a combination of daily oral care, symptom relief and professional guidance.

Sip Water Regularly

Small, frequent sips of water may help keep the mouth moist.

Patients should follow any fluid restrictions provided by their medical team.

Consider Sugar-Free Gum or Lozenges

For patients who can safely chew or suck lozenges, sugar-free products may help stimulate saliva.

Products containing xylitol may be an option, depending on individual tolerance and medical advice.

Ask About Saliva Substitutes

Artificial saliva products, oral moisturising gels and dry-mouth sprays may provide temporary relief.

Your dentist or oncology team can recommend suitable products.

Avoid Alcohol-Containing Mouthwashes

Alcohol-containing oral rinses can worsen dryness or irritation in some patients.

A gentle, alcohol-free product may be more appropriate.

Limit Irritating Foods and Drinks

Acidic, spicy, very salty or excessively dry foods may worsen discomfort.

Maintain Good Oral Hygiene

Dry mouth increases the importance of preventive dental care because saliva normally helps protect teeth against decay.

Your dentist may recommend additional fluoride measures depending on your individual risk.

Important: Do not start prescription medications intended to stimulate saliva without medical assessment. Their suitability depends on your medical condition and treatment.

Yes. Persistent dry mouth can increase the risk of tooth decay.

Saliva helps protect tooth enamel by washing away food debris, neutralising acids and supporting remineralisation.

When saliva production decreases, these protective effects are reduced.

Patients may also experience changes in diet, including more frequent snacking or sipping flavoured drinks to manage nausea or dryness.

These factors can further increase the risk of cavities.

How to Protect Your Teeth

• Brush twice daily with fluoride toothpaste.

• Clean between your teeth as recommended by your dentist.

• Choose water rather than sugary drinks when possible.

• Discuss additional fluoride protection with your dentist.

• Attend dental examinations according to your healthcare team's recommendations.

If you notice new sensitivity, toothache or visible changes in your teeth, arrange a dental assessment.

Mouth sores are another possible complication of certain cancer treatments.

One important cause is oral mucositis, which involves inflammation and injury to the tissues lining the mouth.

Mucositis may develop during some chemotherapy regimens, stem cell transplant treatments or radiation directed at the head and neck.

Certain targeted therapies and immunotherapies can also cause oral lesions, although their appearance and underlying mechanisms may differ.

Symptoms of Oral Mucositis

Common symptoms include:

• Redness inside the mouth

• Tender or swollen oral tissues

• Painful ulcers

• Burning sensations

• Difficulty chewing

• Pain when swallowing

• Sensitivity to certain foods

• Difficulty brushing teeth

In more severe cases, mouth sores may interfere with eating, drinking and daily oral care.

Patients should inform their oncology team when symptoms begin rather than waiting for them to become severe.

No.

Mouth sores can develop for several reasons.

Possible causes include:

• Treatment-related mucositis

• Oral fungal infections

• Viral infections

• Trauma from sharp teeth or dentures

• Dry mouth

• Other medication-related reactions

These conditions can require different treatments.

For example, an oral fungal infection may require antifungal medication, while mucositis management focuses on supportive care and treatment-specific measures.

This is why persistent or painful oral lesions should be evaluated by a qualified healthcare professional.

Do not assume that every mouth ulcer during chemotherapy is harmless or simply an expected side effect.

Mouth sore management should be guided by the oncology team, especially when symptoms are severe.

Several supportive measures may help reduce irritation.

Use a Soft Toothbrush

A soft-bristled toothbrush can help minimise trauma to sensitive oral tissues.

If brushing becomes painful or bleeding occurs, ask your healthcare team how to adapt your routine.

Choose Gentle Foods

Soft, moist foods may be easier to eat.

Examples include:

• Soft porridge

• Mashed vegetables

• Scrambled eggs

• Smooth soups served at a comfortable temperature

• Soft rice

• Other foods recommended by your care team

Food choices should also take into account nutritional needs and any infection-prevention instructions.

Avoid Irritating Foods

Spicy, acidic, rough or very hot foods may aggravate painful tissues.

Use Recommended Mouth Rinses

Your oncology team may recommend a gentle saline or sodium bicarbonate rinse.

For patients who have been advised that such rinses are appropriate, a commonly used preparation is ¼ teaspoon of salt and ¼ teaspoon of baking soda in approximately 240 mL of water.

Rinse gently and spit out the solution. Prepare it fresh and follow your treatment team's instructions, particularly if you have swallowing difficulties or other restrictions.

Ask About Pain Management

If mouth sores interfere with eating or drinking, your oncology team may recommend appropriate pain-relief treatments or specialised mouth rinses.

Avoid using topical anaesthetics, medicated rinses or over-the-counter ulcer treatments without checking with your healthcare team.

Yes. Damaged oral tissues can create an opportunity for microorganisms to enter the body.

This is particularly concerning when chemotherapy reduces the number of infection-fighting white blood cells.

Possible warning signs include:

• Increasing pain

• Swelling

• White patches

• Unusual discharge

• Worsening redness

• Fever

• Difficulty swallowing

Some symptoms may indicate infection rather than uncomplicated mucositis.

A fever of 38°C or higher during chemotherapy, or the threshold specified by your oncology team, requires urgent medical attention.

Patients should contact their oncology team immediately and follow their fever-management instructions.

The duration varies depending on the treatment and individual patient.

Dry Mouth

Dry mouth may improve when a contributing medication is changed or treatment ends.

However, some patients experience symptoms for longer periods.

The duration depends on the cause and whether salivary gland function has been affected.

Mouth Sores

Chemotherapy-related oral mucositis often develops during a treatment cycle and may improve as the oral tissues recover.

However, the timing and severity vary.

Some cancer therapies can cause recurring or persistent oral symptoms.

Your oncology team can provide expectations based on your specific treatment regimen.

Dental care during chemotherapy requires individual assessment.

Routine examinations and certain non-invasive treatments may be possible depending on the patient's condition.

However, procedures that involve bleeding or tissue injury may require additional precautions.

Your dentist may need to consider:

• Current chemotherapy medications

• Treatment schedule

• White blood cell counts

• Platelet counts

• Active oral infections

• Mouth sores

• Healing capacity

• Recommendations from the oncology team

Dental extractions, invasive gum treatment and other surgical procedures should be coordinated with the treating oncology team.

Do not discontinue prescribed cancer medication to undergo dental treatment without medical advice.

A consistent oral care routine can help protect the teeth and gums during cancer treatment.

Morning

• Gently brush with a soft toothbrush and fluoride toothpaste.

• Rinse with a suitable non-irritating rinse if recommended.

• Apply an approved oral moisturising product if needed.

• Check for new sores or unusual changes.

Throughout the Day

• Sip water regularly if medically appropriate.

• Keep the lips moisturised.

• Choose foods that are comfortable to eat.

• Avoid frequent sugary drinks.

• Use prescribed or recommended oral care products as directed.

Evening

• Brush gently before bed.

• Clean between the teeth if safe and comfortable.

• Use a recommended dry-mouth product if needed.

• Check for swelling, bleeding or persistent ulcers.

Patients with severe mucositis, significant bleeding or low blood counts may require a modified routine recommended by their care team.

Seek prompt medical advice if you experience:

• Severe or increasing mouth pain

• Difficulty eating or drinking

• Persistent vomiting or dehydration

• Significant oral bleeding

• Swelling of the mouth, gums or face

• White patches or suspected infection

• Rapidly worsening mouth ulcers

• Difficulty swallowing

Contact your oncology team immediately if you develop a fever during chemotherapy.

If you have difficulty breathing, severe swelling affecting the airway or an inability to swallow saliva, seek emergency medical care.

For tooth sensitivity, broken fillings, gum inflammation or other dental concerns, inform your dentist about your cancer treatment so that appropriate care can be coordinated.