Mouth issues

Mouth sores are areas that might look like cuts or ulcers in the mouth. This is known as mucositis.

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"I ended up in hospital because my mouth was so sore that I couldn't eat or drink. Once I was told how to manage this my mouth was so much better"

What is Mucositis?

Chemotherapy kills rapidly growing cells, such as cancer cells. Some healthy cells in the body also divide and grow rapidly, including the cells that line the inside of the mouth. Unfortunately, these healthy cells are also damaged. Damage to the cells in the mouth make it difficult for the mouth to heal itself and to fend off germs, leading to sores and infection.

Chemotherapy can also impair the body’s immune system. With an impaired immune system, viruses, bacteria, and fungi can more easily infect the mouth, causing sores or making them worse.

Mouth sores usually develop a few days after treatment and disappear within 2-3 weeks after stopping treatment. This occurs alongside when the immune system is at its lowest during treatment. When the immune system recovers, the mouth lining usually does too.

Causes of mucositis

  • Chemotherapy kills lymphoma cells and healthy cells in the mucous membranes
  • Radiotherapy kills lymphoma cells and healthy cells in the mucous membranes
  • After stem cell transplant. This is caused by the high dose chemotherapy and immunosuppressive drugs given as part of the transplant

What to look out for

  • Sores in mouth that may be red
  • Swelling in the gums, mouth, or throat
  • Pain or discomfort when chewing and swallowing
  • White or yellow patches in the mouth or on the tongue
  • Increased mucus in the mouth
  • Heartburn or indigestion

Prevention and self-management

  • Get a dental check-up before treatment. Manage any unresolved dental issues
  • Tell the doctor if you are prone to mouth sores
  • Practice good dental hygiene. Keep teeth, gums, and mouth clean
  • Use a soft-bristle toothbrush for brushing teeth and a mild fluoride toothpaste
  • Stop smoking or cut down
  • Eat a diet rich in fruit and vegetables. Try eating soft food such as scrambled eggs and soup
  • Drink plenty of fluids
  • Coating agents
  • Avoid alcohol especially spirits as they can irritate the lining of the mouth
  • Sucking on ice during chemotherapy
  • Avoid spicy and acidic food
  • Avoid citrus drinks like lemon or orange
  • Mouth rinses. Salt water or a combination of water and baking soda. Aim to do every two hours while awake. Avoid mouthwashes with alcohol.
  • Avoid medication containing alcohol such as mouth wash
  • Apply lip balm to keep lips moist


  • Oral anaesthetics such as xylocaine jelly
  • Topical painkillers such as Bonjela Gel
  • Oral painkillers such as Ibuprofen and paracetamol
  • Antifungal medication such as nystatin suspension
  • Antibacterial mouthwash such as Listerine with zero alcohol
  • Antivirals such as Famvir or Valtrex tablets
  • Antibiotics are given if an infection develops
  • Palifermin is a growth factor that boosts the growth of new cells in the mucous membrane

Support and information

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