Inflammatory bowel disease (IBD) is a term mainly used to describe 2 conditions: ulcerative colitis and Crohn's disease.
Ulcerative colitis only affects the colon (large intestine). Crohn's disease can affect any part of the digestive system, from the mouth to the bottom (anus).
People of any age can get IBD, but it's usually diagnosed between the age of 15 and 40.
Get advice about coronavirus and IBD:
The symptoms of IBD include:
Not everyone has all of these symptoms, and some people may have extra symptoms, including a high temperature, being sick (vomiting) and anaemia.
The symptoms of IBD can come and go. There may be times when the symptoms are severe (a flare-up), followed by long periods when there are few or no symptoms at all (remission).
There's currently no cure for ulcerative colitis or Crohn's disease.
If you have mild ulcerative colitis, you may need minimal or no treatment and remain well for prolonged periods of time.
Treatment aims to relieve the symptoms and prevent them returning, and includes specific diets, lifestyle changes, medicines and surgery.
Medicines used to treat ulcerative colitis or Crohn's disease include:
It's estimated that 1 in 5 people with ulcerative colitis have severe symptoms that do not improve with medicine. In these cases, surgery may be necessary to remove an inflamed section of large bowel (colon).
Around 60 to 75% of people with Crohn's disease will need surgery to repair damage to their digestive system and treat complications of Crohn's disease.
It's unclear what causes IBD, but it's thought to be caused by a combination of factors, including:
People who smoke are twice as likely to get Crohn's disease than non-smokers.
IBD is not the same as irritable bowel syndrome (IBS), which is a common condition that causes symptoms such as: