A colonoscopy requires a laxative either in liquid or tablet form to prepare the colon for this procedure, states the Mayo Clinic. However, the type of laxative prescribed by doctors may be their preferred choice. In some cases, doctors recommend a liquid laxative the night before the procedure.
Usually, a persons needs to drink a gallon of this laxative, reports Harvard Medical School. However, another method involves the person taking half this dose the night before the procedure and the other half the morning of the test. Most of the liquid laxatives, which are available under different brands, contain polyethylene glycol. Other doctors may prefer to have the person take a sodium phosphate tablet, according to WebMD. There is also an oral solution of sodium phosphate used for a bowel prep.
A colonoscopy is a test used to detect different problems in the colon like polyps or cancer,explains Harvard Medical School. For proper viewing of the colon, it must be totally clean..