Crohn's disease
Crohn's disease is a long-term condition that causes inflammation of the lining of the digestive system.
The symptoms of Crohn's disease vary, depending on which part of the digestive system is inflamed.
The exact cause of Crohn's disease is unknown. Most researchers think it's caused by a combination of factors.
A number of different tests may be needed to diagnose Crohn's disease, as it has similar symptoms to several other conditions.
There's currently no cure for Crohn's disease, but treatment can improve the symptoms.
People with Crohn's disease are at risk of developing a number of complications.
Author William Fiennes has lived with Crohn's disease since he was a teenager.
Joseph Barr talks about managing Crohn's disease with medication and how he can still play the sports he loves.