Medically reviewed by Deborah Weatherspoon, Ph.D., R.N., CRNA — Written by the Healthline Editorial Team — Updated on May 8, 2020

Overview

Inflammatory bowel disease (IBD) represents a group of intestinal disorders that cause prolonged inflammation of the digestive tract.

The digestive tract comprises the mouth, esophagus, stomach, small intestine, and large intestine. It’s responsible for breaking down food, extracting the nutrients, and removing any unusable material and waste products.

Inflammation anywhere along the digestive tract disrupts this normal process. IBD can be very painful and disruptive, and in some cases, it may even be life-threatening.

Learn all about IBD, including the types, what causes it, complications, and more.

What are the main types of inflammatory bowel disease?

Many diseases are included in this IBD umbrella term. The two most common diseases are ulcerative colitis and Crohn’s disease.

Crohn’s disease can cause inflammation in any part of the digestive tract. However, it mostly affects the tail end of the small intestine.

Ulcerative colitis involves inflammation of the large intestine.

What causes inflammatory bowel disease?

The exact cause of IBD is unknown. However, genetics and problems with the immune system have been associated with IBD.

Genetics

You might be more likely to develop IBD if you have a sibling or parent with the disease. This is why scientists believe IBD may have a genetic component.

The immune system

The immune system may also play a role in IBD.

Normally, the immune system defends the body from pathogens (organisms that cause diseases and infections). A bacterial or viral infection of the digestive tract can trigger an immune response.

As the body tries to fight off the invaders, the digestive tract becomes inflamed. When the infection is gone, the inflammation goes away. That’s a healthy response.

In people with IBD, however, digestive tract inflammation can happen even when there’s no infection. The immune system attacks the body’s own cells instead. This is known as an autoimmune response.

IBD can also occur when the inflammation doesn’t go away after the infection is cured. The inflammation may continue for months or even years.