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Definition & Facts

Appendicitis, an inflammation of your appendix, is the most common cause of acute abdominal pain requiring surgery. Untreated, it can lead to serious complications, such as peritonitis or an abscess.

A young man looking pained and holding his hand on his stomach.

Symptoms & Causes

Appendicitis symptoms include abdominal pain, lack of appetite, vomiting, constipation, or diarrhea. See a doctor or go to the emergency room right away if you think you or your child has appendicitis. Quick treatment prevents most complications.


To diagnose appendicitis, a doctor reviews your symptoms and medical history; performs a physical exam; and may order urinalysis, blood tests, or a pregnancy test. Imaging tests, such as abdominal ultrasound, CT scan, and MRI scan, help confirm an appendicitis diagnosis or show other causes of your abdominal pain.


Doctors typically treat appendicitis with antibiotics and with surgery to remove the appendix, either by laparoscopic surgery or a laparotomy. Prompt surgery decreases your chances of a burst appendix. Doctors use special care for treating a burst appendix, abscess, or peritonitis. Some mild cases of appendicitis may be treated with antibiotics alone.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support basic and clinical research into many digestive disorders.

Your Digestive System & How It Works

The digestive system is made up of the gastrointestinal (GI) tract—also called the digestive tract—and the liver, pancreas, and the gallbladder. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus.

Last Reviewed July 2021

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Thomas H. Chun, M.D., M.P.H., Hasbro Children’s Hospital