The Small Bowel: Small Intestine and Digestive Health

The small bowel, also called the small intestine, is part of the digestive system. It connects the stomach to the large bowel and plays an important role in digesting food and absorbing nutrients.

This article is for general information only. If you have ongoing abdominal pain, vomiting, unexplained weight loss, bleeding or persistent bowel changes, speak with a doctor.

What Is the Small Bowel?

The small bowel is a long tube that helps break down food and absorb nutrients. It comes after the stomach and before the large bowel. Although it is called “small,” it is actually long; the word small refers more to its narrower width compared with the large bowel.

Main Parts of the Small Bowel

The small bowel has three main parts: the duodenum, jejunum and ileum. Food moves from the stomach into the duodenum, then through the jejunum and ileum before reaching the large bowel.

The ileum connects to the first part of the large bowel. This connection is important in digestion and in some types of bowel surgery.

What Does the Small Bowel Do?

The small bowel helps digest food and absorb nutrients such as proteins, fats, carbohydrates, vitamins and minerals. After nutrients are absorbed, remaining waste passes into the large bowel, where water is absorbed and stool is formed.

For more about the large bowel, read our The Large Bowel: Colon, Rectum and Bowel Cancer Basics article.

Small Bowel and Cancer

Most bowel cancers discussed as colorectal cancer start in the colon or rectum, not the small bowel. Cancer of the small bowel is less common than colorectal cancer. However, symptoms in the digestive system should still be checked if they are persistent or unexplained.

For colorectal cancer basics, read our What Is Bowel Cancer? guide.

Small Bowel and Stoma Surgery

In some bowel cancer operations, a stoma may be created using part of the small bowel. This is called an ileostomy. An ileostomy allows waste to leave the body through an opening in the abdomen into a stoma bag.

For more information, read our Types of Stoma and How the Stoma Works articles.

Symptoms to Discuss With a Doctor

Digestive symptoms can have many causes. Seek medical advice if you have ongoing abdominal pain, vomiting, unexplained weight loss, blood in the stool, persistent diarrhoea, severe constipation or symptoms that are unusual for you.

Final Thoughts

The small bowel plays an important role in digestion and nutrient absorption. While colorectal cancer usually starts in the large bowel, understanding the small bowel can help explain digestion, ileostomy surgery and bowel health more clearly.