An upper GI and small bowel series is done in a radiology department.

You may get an injection of a medicine that slows muscle movement in the small intestine. This makes it easier to see the structures of your organs on the x-rays.

Before the x-rays are taken, you must drink 16 to 20 ounces (480 to 600 milliliters) of a milkshake-like drink. The drink contains a substance called barium, which shows up well on x-rays.

An x-ray method called fluoroscopy tracks how the barium moves through your esophagus, stomach, and small intestine. Pictures are taken while you sit or stand in different positions.

The test most often takes around 3 hours but can take as long as 6 hours to complete.

A GI series may include this test or a barium enema.

You may have to change your diet for 2 or 3 days before the test. In most cases, you will not be able to eat for a period of time before the test.

Be sure to ask your health care provider if you need to change how you take any of your medicines. Often you can continue taking the medicines you take by mouth. Never make any changes in your medicines without first talking to your provider.

You will be asked to remove all jewelry on your neck, chest, or abdomen before the test.

This test may cause mild bloating but no discomfort most of the time. The barium milkshake feels chalky as you drink it.

This test is done to look for a problem in the structure or function of your esophagus, stomach, or small intestine.

A normal result shows that the esophagus, stomach, and small intestine are normal in size, shape, and movement.

A normal result may vary depending on your overall health. Talk to your provider about the meaning of your specific test results.

Abnormal results in the esophagus may indicate the following problems:

• Achalasia
• Diverticula
• Esophageal cancer
• Esophageal narrowing (stricture) - benign
• Hiatal hernia
• Ulcers

Abnormal results in the stomach may indicate the following problems:

• Gastric cancer
• Gastric ulcer - benign
• Gastritis
• Polyps (a tumor that is usually noncancerous and grows on the mucus membrane)
• Pyloric stenosis (narrowing)

Abnormal results in the small intestine may indicate the following problems:

• Diverticulosis
• Malabsorption syndrome 
• Narrowing (stricture)
• Swelling and irritation (inflammation) of the small intestines
• Tumors
• Ulcers

The test may also be done for the following conditions:

• Annular pancreas
• Duodenal ulcer
• Gastroesophageal reflux disease
• Gastroparesis
• Intestinal obstruction
• Lower esophageal ring
• Primary or idiopathic intestinal pseudo-obstruction

You are exposed to a low level of radiation during this test, which carries a very small risk for cancer. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits.

Pregnant women should not have this test in most cases. Children are more sensitive to the risks for x-rays.

Barium may cause constipation. Talk to your provider if the barium has not passed through your system by 2 or 3 days after the exam.

After this test, the barium that remains in the body may block details in other imaging tests. For this reason, other imaging tests may be done first.

GI series; Barium swallow x-ray; Upper GI series; Small bowel follow through

Agosto O, Dass C, Caroline DF. The stomach. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 20.

Al Sarraf AA, McLaughlin PD, Maher MM. The small intestine, mesentery and peritoneal cavity. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 21.

Carucci LR. Diagnostic imaging procedures in gastroenterology. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 119.

Updated by: Jenifer K. Lehrer, MD, Gastroenterologist, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.