I’ve been asked that question many times, and up until now Ive only been able to give an answer based on theory and on my professional and personal experience with this colon cleansing technique. (If youre not familiar with shanka prakshalana, see my explanation here.)
By theory, dangerous shifts in blood levels of sodium and potassium could result in serious health consequence. By professional and personal experience, I can say Ive never seen it happen, not in hundreds of trials. Of course, just because I havent seen it, that doesnt mean serious electrolyte shifts won’t occur depending on individual circumstances.
As a physician and a scientist, I’ve wished for a research study documenting the safety of shanka prakshalana, real data to support its safety and efficacy. This week I finally located just such as study, and I am happy to share it with you today.
In 1978, quite a long time ago, a physician on an Air Force Base in the Midwest of the United States, Colonel Clint Chambers, designed a study along with a Texas colleague of his, Gray Carter, to look at the ability of bowel irrigation with salt water to prepare the large intestine for colonoscopy or surgery. They werent yogis, at least as far as I know, and I dont imagine either of them had heard the term shanka prakshalana. They based their trial on the textbook theories of how the sodium ion of common table salt (sodium chloride) traverses the gut wall, and they were aware of two prior studies looking at a similar bowel prep tried due to the same deductive reasoning.
Twenty-three patients were cleansed with a physiological solution of salt water, the exact solution recommended for shanka prakshalana. Its the same 0.9% sodium chloride we put into the veins of dehydrated patients in the hospital, but it was administered either by mouth or by a tube into the stomach.
Electrolytes were measured prior to the ingestion of salt water and immediately thereafter. No significant shifts of sodium or potassium were observed.
Doctors judged the efficacy of warm salt water at thoroughly cleansing the colon. Most of the time they gave an excellent rating, and it was at least satisfactory 95% of the time for all patients in this study, inclusive of another set of 14 patients who were given a little potassium and bicarbonate in their salt solutions. That success rate parallels, or even exceeds, any modern pharmaceutical colon cleanse preparation for colonoscopy.
Dr. Chambers and Dr. Carters results are consistent with a previous study in 1976 in which 37 people were given a plain table salt solution as a colon cleansing preparation. After drinking four liters of physiological saline, none of the patients had significant electrolyte shifts. In 1975, Dr. Crapp (really, Im not making that up) and his colleagues successfully cleaned the colons of 47 people with physiological saline. They didnt report any electrolyte abnormalities either.
So why, you may be asking, if shanka prakshalana is such a safe and effective natural method of colon cleansing, did the medical establishment abandon it in favor of other solutions?
The doctors in the 1978 study gave up on asking the patients to drink salt water after a few of them had a difficult time with the taste and volume of liquid needed. It was too salty to enjoy, and it induced vomiting in two. Instead they moved to placement of a tube that is threaded up the nose, down the back of the throat, and then into the stomach with the liquid infused through it. For some reason, the patients apparently liked that better, although having a tube up your nose is not too fun either.
Subsequent studies revealed the dangers and side effects of nasogastric tube placement, and eventually the whole saline irrigation technique of bowel preparation was deemed intolerable by patients. A pharmaceutical company immediately stepped in to make a solution that works by the same physiological principles of the salt flush without the extreme salty taste. That solution, polyethylene glycol or PEG, is still used for colonoscopy preparations today. Marketing and patient satisfaction with PEG left simple saline flushes to disappear from the conversation. Shanka prakshalanas attempt to become mainstream was thwarted, and its trials have been buried in dusty journals from the 1970s.
So, I am happy to be able to say that shanka prakshalana is a safe method for colon cleansing for most people based both on my professional experience and on the scientific literature. I have never found a case report or study indicating otherwise. Still, a theoretical basis for injury exists, and susceptible people should either avoid its use or exercise extreme caution under the direction and care of their personal physician. Anyone with kidney disease, congestive heart failure, high blood pressure or taking medications for high blood pressure, ischemic heart disease, stomach ulcers or pregnancy is at a higher risk of complications.
Shanka prakshalana should never be done at home alone without at least one family member or buddy to keep an eye out, and the first experience should be done under the care and observation of an experienced practitioner.
If you want a safe and natural method of intestinal cleansing for colonoscopy, discuss salt water flushing with your doctor. Below are the scientific references for the articles mentioned above for you to share with your healthcare team.
- Chambers CE, Carter HG. Saline lavage: a rapid, safe, effective method of whole-gut irrigation for bowel preparation. South Med J. 1978 Sep;71(9):1065-6. PDF (162 KB)
- Levy AG, Benson JW, Hewlett EL, Herdt JR, Doppman JL, Gordon RS Jr. Saline lavage: a rapid, effective, and acceptable method for cleansing the gastrointestinal tract.Gastroenterology. 1976 Feb;70(2):157-61.
- Crapp AR, Tillotson P, Powis SJ, Cooke WT, Alexander-Williams J. Preparation of the bowel by whole-gut irrigation. Lancet. 1975 Dec 20;2(7947):1239-40.