Appendicitis is inflammation of the appendix, which is a thin pouch attached to the large intestine on the right side of the abdomen. It is usually about the size of a finger.
The exact cause of appendicitis is not known, but it may be food or faeces (poo) getting lodged in the appendix. The appendix becomes blocked, inflamed, then infected. While appendicitis can occur at any age, it is most common in children and young adults.
If you think that you or someone in your care may have appendicitis, it is important that you see a doctor as soon as possible. If the infected appendix bursts, the infection is likely to spread throughout the abdomen, causing serious problems.
Last reviewed: September 2018