If all you want to do is flush your GI Tract, there are MANY ways, e.g. enemas/colonics, herbal cleanses, etc., etc., etc., although ascorbate is probably the best way. However, you are not getting a long term ascorbate benefit just doing that periodically!
"There are more than ten thousand scientific papers that make it quite clear that there is not one body process (such as what goes on inside cells or tissues) and not one disease or syndrome (from the common cold to leprosy) that is not influenced - directly or indirectly - by vitamin C." -- Dr. Emanuel Cheraskin, M.D., Dr. Marshall Ringsdorf, D.M.D., and Dr. Emily Sisley, THE VITAMIN C CONNECTION.
“I have never seen a patient that Vitamin C would not benefit.” -- Dr. Frederick Klenner, M.D.
As "grist for your mill," I myself have taken a "bowel tolerance" dose (in HEALTH, not illness - http://www.orthomed.com/titrate.htm) of ascorbic acid every day since 1994, amounting to, on average, 30,000 to 60,000 milligrams (approximately 1 to 2 ounces) in 5 to 10 divided doses (and will continue to do so for the rest of my life). This is MY bowel tolerance dosage. Your bowel tolerance dosage may be more, or less, than mine, and will undoubtedly vary depending on your current overall health and diet. Each person must find their own bowel tolerance dose each day (although ingesting ANY ascorbate is MUCH better than none). Virtually any mammal you can name (standardized to 154 pounds/70 kilos) produces a minimum of from 2,000 to 13,000 milligrams of ascorbic acid EVERY day of its life, and under "stress" one was recorded to have produced 100,000 milligrams in 24 hours. Need we wonder why their health always seems to be so much better than ours?