<unk> , often simply called<unk> , is a contrast agent used during X-rays. Specifically it is used to improve visualization of the gastrointestinal tract (esophagus, stomach, intestines) on plain X-ray or computed tomography. It is taken by mouth or used rectally. Side effects include constipation, diarrhea, appendicitis, and if inhaled inflammation of the lungs. It is not recommended in people with intestinal perforation or bowel obstruction. Allergic reactions are rare. The use of<unk>  during pregnancy is safe for the baby; however, X-rays may result in harm.<unk>  is typically made by mixing<unk><unk>  powder with water. It is a non-iodinated contrast media.<unk><unk>  has been known since the Middle Ages. In the United States it had come into common medical use by 1910. It is on the World Health Organization's List of Essential Medicines. Some versions contain flavors to try to make it taste better.
Barium sulfate suspension
Sodium hydroxide
Amylmetacresol
Sodium hypochlorite
Podophyllum resin
Hydrochloric acid
Silver diammine fluoride
Iron sucrose