Sore mouth or gut (mucositis)

The symptoms of mucositis depend on which type you have: oral mucositis or GI mucositis.

If you get oral mucositis, you’ll normally get symptoms five to ten days after chemotherapy, or 14 days after radiotherapy. Symptoms of oral mucositis include:

• a dry mouth, which can lead to mouth and gum infections (although sometimes a dry mouth on its own can just be a side effect of chemotherapy rather than mucositis)
• ulcers or blood blisters (or both) inside your mouth, and sometimes on your tongue or lips
• a sore or painful mouth, which may make it difficult to eat, drink or talk
• bad breath
• oral thrush, an infection caused by a fungus called Candida.

Oral thrush can happen if mouth ulcers become infected. Symptoms include:

• pain in your mouth
• white patches in your mouth that may bleed
• a loss of taste
• cracks at the corner of your mouth.

Different people will experience different levels of severity, or grades, of oral mucositis. For example, we know mucositis can be severe if you have high-dose chemotherapy as preparation for a stem cell transplant. It depends how toxic your treatment is, and how it affects you personally.

Your healthcare team will assess and treat your particular symptoms.

Symptoms of GI mucositis can start up to 14 days after you begin chemotherapy or radiotherapy. The main symptoms are:

• diarrhoea (frequent, watery poos)
• ulcers around your rectum or anus
• bleeding from your gut, which you may notice as blood in your poo
• trouble swallowing because it hurts
• feeling sick
• constipation (difficulty pooing)
• stomach cramps
• bloating.

We have information about managing sickness and vomiting, which can be caused by blood cancer, blood cancer treatment, or GI mucositis.

Normally, the lining of your gut acts as a barrier to stop germs getting into your bloodstream. If you have mucositis, the lining doesn’t work properly, so you’re more likely to get an infection. You’re particularly at risk of infection if your condition or treatment cause a drop in your white blood cell count, so your body can’t fight off germs as well as it usually does.

If you get symptoms of an infection, speak to your healthcare team straight away. Symptoms of an infection include having a high or low temperature, feeling confused, or generally not feeling well.

We have more information about the symptoms of infection and how to manage your risk.