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Mouth sores (mucositis)

Chemo and some targeted drugs can cause painful sores in the mouth and throat.

When it happens

They often show up about a week after treatment and heal in a couple of weeks.

What helps at home

Rinse several times a day with a mix of 1/4 teaspoon baking soda and 1/8 teaspoon salt in 1 cup of warm water (a rinse NCI describes).
Use a soft toothbrush.
Avoid alcohol-based mouthwash, spicy, acidic and crunchy foods.
Eat soft, cool or room-temperature foods.
Keep lips moist with lip balm.
Ask about a numbing rinse or other medicine.

Call your care team now if you have:

You can't eat or drink because of pain
White patches (possible infection)
Fever of 100.4°F (38°C) or higher

Call 911 for trouble breathing, chest pain or signs of stroke.

Drugs on this site linked to mouth sores

Find support

CancerCare: Free counseling, support groups and financial help
Cancer Support Community: Support groups, a helpline and the MyLifeLine online community
Imerman Angels: Free one-on-one matching with a survivor or caregiver mentor
American Cancer Society: 24/7 helpline (1-800-227-2345), rides to treatment, lodging and information

Common questions

What are home remedies for mouth sores from chemo?

A salt and baking soda rinse, soft foods and avoiding irritants. Ask your team before trying anything else.

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write

Not medical advice. This page is general information to help you talk with your care team. It can't replace advice from your doctor or nurse. If you have a fever of 100.4°F (38°C) or higher during treatment, or any symptom that worries you, call your care team now. In an emergency, call 911.