Patients should follow their physician’s advice about the preparatory steps that may be necessary before a barium x-ray. These may include dietary restrictions and modifications to a patient’s regimen for taking over-the-counter and prescription medications.  

Before an upper GI barium x-ray, patients may receive special instructions such as how long to fast prior to testing. Prior to a lower GI barium test, the lower gastrointestinal tract must be emptied of its contents. These steps may include:

• Minimum-residue diet, restricted to low-fiber foods allowing only minimal solids in the intestines, such as lean meat, refined cereals, pasta and liquids. Typically this diet starts two or three days before the test.
  
  
• Clear liquids only. This stricter diet may be required up to three days before testing, or the patient may be started on a minimum-residue diet and then limited to clear liquids a day or two before testing.
  
  
• Abstention from medications. The physician may have the patient stop taking some or all medications starting 12 to 24 hours before testing.
  
  
• Fasting. Typically, fasting begins 12 hours before testing.
  
  
• Laxatives, enemas, suppositories. Any combination of these may be recommended the evening before and/or the morning of the test.

Patients should also inform their physician about any previous allergic reactions to barium sulfate or allergies to foods, preservatives or dyes. Other conditions that may affect the use of barium sulfate include:

• Asthma.
  
  
• Hay fever.
  
  
• Cystic fibrosis. Risk of small-bowel blockage is increased.
  
  
• Dehydration. Barium sulfate my cause severe constipation.
  
  
• Intestinal blockage or perforation. Barium sulfate can exacerbate this condition.

Women who are pregnant are discouraged from having barium x-rays due to the potential for radiation exposure to the fetus.