Upper gastrointestinal series (or study), whereas the barium enema is called a lower gastrointestinal series (or study). In upper gastrointestinal series examinations, the barium sulfate is mixed with water and swallowed orally, whereas in the lower gastrointestinal series (barium enema), the barium contrast agent is administered as an enema through a small tube inserted into the rectum. Barium X-ray examinations are useful tools for the study of appearance and function of the parts of the gastrointestinal tract. They are used to diagnose and monitor esophageal reflux, dysphagia, hiatus hernia, strictures, diverticula, pyloric stenosis, gastritis, enteritis, volvulus, varices, ulcers, tumors, and gastrointestinal dysmotility, as
Colon cleansing tubes to inject water, sometimes mixed with herbs or with other liquids, into the colon via the rectum using special equipment. Oral cleaning regimens use dietary fiber, herbs, dietary supplements, or laxatives. People who practice colon cleansing believe that accumulations of putrefied feces line the walls of the large intestine and that these accumulations harbor parasites or pathogenic gut flora, causing nonspecific symptoms and general ill-health. This "auto-intoxication" hypothesis is based on medical beliefs of the Ancient Egyptians and Greeks and was discredited in the early 20th century. There is no scientific evidence for the alleged benefits of colon cleansing.