Mouth Sores

Mouth sores occur when the lining inside the mouth breaks down and causes sores to form; this may lead to infection and mouth sensitivity. It most commonly occurs as a result of chemotherapy and radiation therapy for mouth cancer.

What is oral mucositis?

Oral Mucositis is when the lining inside the mouth breaks down and when sores form, infection can occur, and the mouth becomes more sensitive. It is most common during mouth cancer chemotherapy and radiation therapy.

What causes oral mucositis?

  • Chemotherapy
  • Radiation therapy
  • Poor oral/dental health
  • Smoking/chewing tobacco/drinking alcohol
  • Dehydration
  • Low body mass index (18.0 and below)
  • Diabetes
  • Kidney disease
  • Females have an increased risk

What happens when people have mouth sores?

  • Inflammation of the mouth
  • Little cuts in the mouth
  • Ulcers in the mouth
  • Tender gums
  • Sore throat
  • Increased mucus in the mouth
  • Pain
  • Blood in the mouth

What should I eat when I have mouth sores?

When mucositis occurs, eat foods that are soothing to the mouth, plain without seasoning, and that still provide nutrients.

Easy to chew foods

  • Scrambled eggs
  • Baby food
  • Cream of wheat/oatmeal
  • Apple sauce
  • Creamy peanut butter
  • Low sodium soups/broths

Cold or room temperature food

  • Ice cream
  • Popsicles
  • Gelatin
  • Milkshakes
  • Smoothies
  • Yogurt/greek yogurt

Bland foods

  • Plain rice
  • Plain pasta
  • Plain baked potatoes
  • Plain mashed potatoes
  • White bread/toast
  • Cooked squash, carrots, green beans, and corn
  • Bananas
  • Tofu
  • Baked, unseasoned fish and chicken

What should I NOT eat when I have mouth sores?

When mucositis occurs, avoid eating foods that can irritate the mouth and cause pain in a sensitive mouth.

Acidic foods

  • Oranges
  • Grapefruits
  • Lemons/limes
  • Tomatoes/ketchup
  • Tomato sauce
  • Vinegar
  • Fruit juice with added sugars
  • Mustard
  • Pickles

Spicy/seasoned foods

  • Hot sauce
  • Curry spice
  • Enchilada sauce
  • Buffalo wings
  • Salsa
  • Chips with "hot" flavor

Crunchy foods

  • Granola
  • Saltine crackers
  • Potato/tortilla chips
  • Hard breads (baguettes, ciabatta bread, French bread)

Salty foods

  • French fries
  • Soy sauce
  • Pretzels
  • Beef jerky
  • Instant ramen noodles
  • Salted mixed nuts
  • Deli meats
  • Salad dressing


What else can I do wehn experiencing mouth sores?

  • Cook all foods until tender, easy to chew
  • Eat frequent, small meals
  • Cut foods into bite-sized pieces or puree
  • Drink liquids though a straw
  • Suck on ice chips
  • Drink nutritional milkshakes if necessary (Boost Plus, Prosure, Ensure, etc.)
  • Keep your mouth clean and inspect daily for sores or patches

When should I call my healthcare provider about mouth sores?

  • If the sores make it too difficult for you to eat and drink
  • When sores do not heal over time or get worse
  • If the sores begin to be so painful that you cannot perfrom everyday tasks
  • If your oral temperature reaches above 100.4 degrees F
  • If you begin to have uncontrollable sweats or chills
  • If you feel so tired that you cannot perform everyday functions