Colonic hydrotherapy, or irrigation, is promoted regularly in popular magazines and the media. Celebrity fans of the therapy - which uses filtered water to flush the colon, the final section of the digestive system - have transformed it from taboo to trendy in recent years.
Hydrotherapists tout the "detoxifying" benefits of colonic cleanses, which include improvements in well-being, energy, bowel movements, mood, energy, immune system and even weight loss. Each treatment takes 30 to 45 minutes and uses up to 60 litres of water injected into the colon via the rectum (the lower part of large intestine that stores stool). Herbs and other liquids, such as coffee, are sometimes mixed with the water.
Hydrotherapists believe the accumulation of faecal matter can form a thick layer of waste on the colonic wall and this can put unnecessary strain on the surrounding organs and the nervous system, and interfere with the absorption of essential nutrients from the colon.
Toxins in the accumulated faecal matter are absorbed into the bloodstream and spread throughout the body, leading to many immune system-related diseases.
No colorectal surgeon has ever observed compacted faeces accumulating on the colonic wall, leaving a narrow central passageway as described by hydrotherapists. Faecal matter in the right colon is liquid and it becomes more solid as it moves to the left colon.
Therefore, there is less and less contact between the toxins deep within the solid faecal masses and the absorptive colon lining. Introducing a large volume of water can actually break up this solid faecal packaging. Theoretically, this can disseminate the toxins and increase the chances of absorption.
Besides, the infusion of a large volume of liquid into the left colon can increase the hydrostatic pressure, which may cause both toxins and bacteria to permeate the colonic wall and leak into the body's circulation. Fibre can help by packaging the bacterial mass into hard lumps - a natural and better way to keep toxins under control.
Practitioners claim that the therapy can exercise and tone the bowel, improving the clearing of waste. But the colonic wall is made of smooth muscle and it cannot be trained or toned up by exercise.
They also claim the therapy is naturopathic (utilising the healing power of nature). Cleansing products, especially coffee, are said to contain ingredients that may improve the function of the gastrointestinal tract, repair the interior of the colon, normalise intestinal muscle contractions and improve good bacterial balance. Practitioners advise more frequent use will provide more benefits.
But excessive caffeine intake can cause restlessness, vomiting, chills, heart failure, heart attack, muscle twitching, diarrhoea, confusion and irritability. Withdrawal symptoms such as anxiety can also occur.
Hydrotherapists say the therapy is useful for some colonic diseases such as diverticulosis, whereby pouches form in the wall of the colon. However, the bowel wall over the area of these pouches is thinner.
Hydrotherapy may lead to bacteria in the bloodstream, blood-poisoning and perforation of the thin-walled colon.
Hydrotherapists say the bowel will better absorb nutrients and be less likely to absorb toxins from the intestines after the therapy.
But they also say the colon cannot absorb the nutrients and eliminate the waste appropriately if it's blocked with faecal matter and waste. The claims are self-contradictory. If the absorptive function is blocked and the nutrients cannot be absorbed, then how can the toxins be absorbed?
In fact, the nutrients are absorbed by the small intestines and right colon. Faecal matter in the left colon is solid waste material, consisting of indigestible residues of food, bacteria and dead cells from the lining of the digestive tract that is to be expelled from the body through the anus.
Dispersing the faecal matter in a fluid environment after hydrotherapy can actually increase the risk of absorption of toxins as the waste material is mixed with water and forced to the right side, where it can be absorbed.
Hydrotherapy has some serious reported complications, including rectal perforation from improper equipment insertion, amoebic infection from poorly sterilised equipment, aplastic anaemia, disseminated abscesses, fluid and electrolyte imbalance, malnutrition and dependence.
In conclusion, there is no scientific evidence to support any of the alleged benefits of colon hydrotherapy. The claims made by manufacturers and practitioners are based on a flawed understanding of the body. Colonic hydrotherapy may in fact cause the dissemination and absorption of toxins and bacteria into the body.
It also carries some risks to damage the rectum and the colon.
Dr Edmond Cheuk is a specialist in general surgery