and drink normally, with special attention to plenty of fluids. The barium sulfate is excreted through defecation, so extra fluid intake helps prevent constipation, which is a possible side effect (see Johns Hopkins Medicine Health Library for an example of a possible patient education instruction sheet). Side effects Some patients with allergies or sensitive stomachs may choose to discuss alternatives to the barium sulfate suspension with their radiologist, but most patients find the common side effects more of an annoyance than a serious problem. Among the possible side effects, listed on MedlinePlus are nausea and diarrhea, which may begin as soon as 15 minutes after consumption begins and may persist through the day after the test is completed. Other side effects may include a feeling of weakness, pale skin, ringing in the ears, constipation, and vomiting. Patients may be strongly encouraged to avoid vomiting, as expelling a substantial quantity of the suspension may void its effect on the CT scan and produce unusable results, requiring a retest. As with most medications, if any severe side effects are experienced the patient is encouraged to contact their doctor or local poison control center immediately. Taste and texture Oral barium sulfate suspensions are sometimes described as having the consistency of a very thick glass of milk, or a very thin milkshake. Some patients may experience the texture as a chalky liquid, similar to calcium carbonate containing liquid antacids and with a slight medicinal taste. Dr. Roscoe Miller, in his article, "Flavoring Barium Sulfate", noted that taste thresholds vary per person, and patient toleration of the medicine also varies. The suspension is typically homogeneous, smooth, and white in color. When the suspension is stored at room temperature (some labels suggest 25 °C), "warm, thick milk" is a common description of the general weight and consistency of the drink. If the test requires the suspension to travel quickly through upper gastrointestinal tract it may be given chilled. Many preparations of barium sulfate have added flavors to make them easier to tolerate. In general, the flavor is considered unpleasant, and is dependent on the exact makeup of the drink. Artificial flavors vary per preparation, and include vanilla, banana, pineapple, lemon, and cherry, among others. Because of the ease of the actual test, the paced two-hour consumption of the barium sulfate suspension is often considered the worst part of a CT scan. References External links Radiocontrast agents