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4 Uses of Enema + Side Effects

Written by Carlos Tello, PhD (Molecular Biology) | Last updated:
Evguenia Alechine
Puya Yazdi
Medically reviewed by
Evguenia Alechine, PhD (Biochemistry), Puya Yazdi, MD | Written by Carlos Tello, PhD (Molecular Biology) | Last updated:

Historically called clyster, an enema is a procedure that has been utilized for centuries. This procedure has been used for a variety of reasons such as constipation, bowel disorders, and colon cleansing.

Today, an enema is performed in a medical setting or even at home. Keep reading to learn about the different types, uses, and clinically proven benefits of this procedure.

What Is an Enema?

An enema is a procedure in which liquid is injected through the rectum, expelling its contents into the lower bowel.

This procedure has been used for centuries in different forms. Although the apparatus has changed throughout the years, the basic principles of how and why it is used remain the same.

What are Enemas Used For?

Some people may feel uncomfortable by the thought of an enema. However, it may be effective in restoring digestive function and other health problems. Its most common uses and benefits include:

  • Bowel stimulant (constipation treatment)
  • Colon cleansing (hygiene and colonoscopy preparation)
  • X-ray imaging (preparation)
  • Medication administration
  • Bowel hygiene

However, milder treatments (such as stool softeners, bulk-forming laxatives, drinking solutions, and suppositories) are preferred whenever possible. Because enemas may cause serious side effects such as kidney problems, rectal bleeding, and dehydration if improperly used, it’s important to use them only as directed by a conventional doctor.

You may find information online about certain types of enemas (e.g., coffee enema) having antioxidant effects and treating cancer, but this is not supported by scientific research [1, 2].

The rest of this article will give you a guideline on the different types of enema, as well its associated uses and side effects.

Types of Enema

Cleansing Enema

A cleansing enema is used to cleanse the bowels and digestive organs.

The 3 main types of cleansing enemas include:

  • Large volume cleansing enema (500 to 1000 mL): Enema solution (differs depending on the purpose of enema) cleanses the colon and most of the large intestine. This type of enema may cause damage to the external tissue of your bowels [3].
  • Small volume cleansing enema (50 to 200 mL): For younger users or elderly patients who may have more sensitive external tissue in their bowels. This rarely causes complications in children [4].
  • Packaged pre-disposable enema: These are enemas designed for use at home for users who can do it themselves. These single-use packages come with sodium phosphate solutions. The largest side effects of these are water and electrolyte imbalances, which can be dangerous for the elderly [5].

Retention Enema

A retention enema is when a specific solution is released into the bowel to be absorbed. This is held in for varying periods of time without expulsion of any of the solution. Even though it may be quite uncomfortable, holding it in allows time for the colon to absorb most of the solution (e.g. medication administration).

Coffee Enema

There is some circulation of information that reports that coffee enemas can treat cancer and have antioxidant effects. These both have been disproven in scientific research, so you must be wary when hearing about such uses of coffee enemas [1, 2].

Proponents of coffee enemas also claim that they improve digestion by stimulating the release of bile, although this effect has only been observed in people drinking coffee [6, 7].

In a pilot study of 34 patients (who needed an endoscopy), those treated with a coffee enema had better imaging results [8].

Importantly, coffee enemas may cause serious health complications, especially if used without medical supervision. In addition to those common to other types of enemas (such as digestive issues from bowel stretching, infections from improperly sterilized kits, and electrolyte imbalances), coffee enemas may cause burns (if the coffee is still hot) and irritation (from coffee’s compounds) in the bowels. Two women even died due to severe electrolyte imbalance from frequent coffee enema use [9, 10, 11, 12].

Salt Water Fleet Enema

Fleet enemas are primarily used for the preparation of a colonoscopy and for constipation. The bowel-cleansing solution of sodium phosphate or sodium chloride mixed with water stimulates bowel movements within minutes of the enema. It is more effective in bowel cleansing for colonoscopy preparation than its oral equivalent, with both having similar side effects (dehydration and electrolyte imbalance) [13].

Barium Enema

A barium enema is an X-ray imaging preparation that physicians use to examine and evaluate the lower intestinal tract. The barium solution used helps provide more clear and accurate imaging results. If proper equipment and careful techniques are used by your medical caregiver during this procedure, complications are very rare [14, 15].

Mineral Oil Enema

Mineral oil enemas are used to treat constipation and to clean out the intestines and digestive organs. For older adults, this type of enema is recommended over fleet enemas. Its use with fleet enema has also been reported to help remove large tar burns [16, 17].

Mechanism of Action

The general mechanism of enemas causes increased pressure and potential irritation of the external tissue in your bowels and anus. Although this may cause harmful effects, enemas are proven to be safe if used correctly [18].

Phosphate Enema

Phosphate enemas (one type of fleet enema) cause stimulation of the external tissue in the bowels. This solution is more concentrated than the layer below the external tissue (hypertonic solution), resulting in the movement of water outside the tissue. This causes pressure changes that ultimately help bowel movements [18].

Salt Water, Tap Water, and Soap Suds Enema

These types of enema solutions also increase pressure in the bowels, promoting evacuation. When used in small volumes, these enemas are less irritating than phosphate enemas [18].

Mineral Oil Enema

Commonly composed of glycerin, this enema causes water movements (osmosis) within the bowels that promote defecation [18].

How to Use an Enema

1) Relieving Constipation

The normal amount of time between bowel movements differs from person to person. Many individuals have constipation, which causes increasingly uncomfortable symptoms the longer it remains untreated. Constipation becomes more prevalent as individuals grow older, and negatively impacts the quality of life [16].

Enemas are an effective procedure to treat constipation. Although the most common treatments are laxatives, enemas may be just as useful. A variety of enema treatments are available, and each of them has characteristics that help in specific cases [19].

Once the enema solution is administered through the anus, it is held there to allow time for the solution to get absorbed and mix with the stool. This softens the stool, and voluntary evacuation of the solution after a few minutes normally results in immediate relief [19].

In an observational study on over 500 children with constipation treated with an enema of small volume soap suds, more than 80% showed positive results without any complications. In an additional study on 79 children with constipation, salt water enema treatment resulted in 62% of the children reporting relief [4, 20].

In another study, over 200 people with constipation were treated with only a milk and molasses enema in the emergency department. Bowel evacuation was successful in 88% of these patients, including 82% of those who had failed to respond to other treatments [21].

2) Cleansing the Colon

Colon cleansing has become increasingly important with the expansion of colon screening. The cleaning is required to ensure that certain aspects of colon screening are not missed due to poor visualization [22].

In one clinical trial, 1,200 patients scheduled for barium x-ray imaging were given an enema for colon cleansing. Given a combination of laxatives and water purge, 52% to 80% of their colons were clean. When an additional tap water enema was given an hour before a colon examination, 96% of the colons were clean of fecal matter [23].

In an observational study, a group of 123 patients who also required a barium X-ray were given cleansing enemas to clean their colon. Patients who completed more rounds of enema had significantly less fecal matter present in their bowels [24].

The average person has a variety of bacteria and fecal matter buildup in the colon. Although this may only result in no or slight complications such as bloating, some people believe this can lead to more serious problems such as chronic diseases.

Although there is a widespread practice of colonic cleansing among some natural health practitioners, there is no evidence to support its use to improve and promote health [25].

3) Helping Diagnose Colon Disease

A double-contrast barium enema is a useful technique utilized by health professionals to get x-ray visualizations of the colon and rectum. A high-quality examination can be completed in most patients, which makes it a powerful tool for the recognition and diagnosis of any underlying problems in the colon and rectum [14].

This type of enema is less invasive than a colonoscopy, which would be the alternative visualization technique. If a barium enema is completed after a colonoscopy, it allows for complete colonic evaluation and diagnosis [26].

In one study, 190 patients with a neoplastic disorder referred for a double-contrast barium enema by a physician were given a colonoscopy. The researchers found that enema may give false positives while colonoscopy may have technical difficulties. They concluded that both techniques are beneficial for visualization, with each having its own drawbacks [27].

In an observational study, over 100 people who had just received an incomplete colonoscopy subsequently received a barium enema. The barium enema revealed the entire colon of 94% of the patients. Additionally, this technique allowed the detection of abnormalities not found in the colonoscopy in 14 patients [26].

Barium enema visualization is best used to detect bulges in the wall of the large intestines (diverticular disease). However, there are superior techniques than a barium enema to detect polyps and inflammatory bowel disease. The optimal method to detect complications is to use a combination of visualization techniques (barium enema, sigmoidoscopy, and colonoscopy) [27, 28].

4) Drug Administration

Enemas can be used to administer drugs through the rectum. This method of drug administration may be useful when the right solution is used. They can be designed specifically for full-body administration (systemic) of the drug, or just for the adjacent tissue (local). An additional advantage is being able to maximize local drug concentrations in the colon [29].

Two of the most commonly used types of enemas for drug administration are sucralfate enemas and vancomycin enemas. Sucralfate is frequently used to treat gut diseases, while vancomycin is an antibiotic [30, 31].

In one observational study, 22 people with inflamed colons were given sucralfate enemas twice a day for 3 weeks. Afterward, 19 of the 22 patients demonstrated clinical improvements. In another study, 6 people with rectal ulcers were given sucralfate retention enemas for 6 weeks. Four of the patients had complete relief of symptoms, while the other 2 experienced marked improvements [32, 33].

A retrospective chart review of 47 people with severe colon infections (Clostridium difficile colitis) was treated with a colonic vancomycin enema. Seventy percent responded with full recovery and thus did not require surgery [34].

Side Effects

There are a variety of different side effects associated with different types of enemas. Because some of them can be dangerous, it’s important to use enemas only as directed by a reputable practitioner and immediately report any unwanted effects caused by their use.

The most common side effects include:

  • Electrolyte imbalance and dehydration
  • Bowel damage
  • Arrhythmia (abnormal heart rhythms)
  • Sepsis
  • Kidney damage
  • Increased chance of HIV for MSM

Electrolyte imbalance and dehydration is the most common side effect associated with phosphate enemas. One trial in adults found severe electrolyte shifts in the blood following phosphate enemas. A 90-year old patient given enemas to treat constipation showed severe signs of dehydration [35, 36].

It is critical that a patient using phosphate enemas promptly evacuates, because electrolyte disturbances (hyperphosphatemia) may be life-threatening [18, 37].

Cleansing enemas can perforate and damage the bowels. In a clinical trial on 24 healthy volunteers, those using soap sud and tap water solution enemas damaged the outer skin layers of their bowels. Perforation, electrolyte imbalances (hyperphosphatemia), and sepsis may cause death in up to 4% of the cases (especially in the elderly) [3, 37].

There is a case of a 72-year old patient who got a colonic perforation during a barium enema due to an excess of barium being used. Damage and perforation of the bowels are preventable but not rare [38].

Cases of arrhythmia (abnormal heart rhythms) have resulted from the use of different enemas. Out of 58 patients over 60 years old, 40% developed new arrhythmias during a barium enema. Additionally, non-hazardous heart arrhythmia is possible during small-bowel enemas in elderly patients.

There have been incidents of sepsis (systemic infection) in small infants as a result of contrast enemas. In an observational study of 160 premature babies who received contrast enemas during intensive care, 21 were reported to have clinical sepsis [39].

Kidney failure is prevalent among elderly people who undergo fleet enemas. Eleven elderly patients received fleet enemas for constipation. Kidney failure was found in all the patients after the enema, 5 of whom died as a result [40].

Studies have associated HIV incidence and recent enema use. In one report, over 95% of HIV-positive MSM in their sample used an enema before anal sex and 45.8% used an enema afterward [41].


To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. Talk to your healthcare provider to find out how enemas might interact with something else you are taking.

Given the effect of fleet enemas on the kidneys, electrolytes, and bowels, there may be some interactions with other drugs you are taking [35, 40, 3].

Most painkillers (i.e., ibuprofen) put a strain on the kidneys as well. If you are taking painkillers in conjunction with performing fleet enemas, it is recommended to consult your doctor to make sure it is safe to do so, as they both can cause kidney damage [42].

Additionally, since enemas stimulate bowel movements, most drugs taken orally may not be digested as effectively as they would normally. A change in the rate of stomach emptying alters the absorption amount of orally ingested drugs. Faster digestion may cause less drug absorption, making the drug less effective [43].

Laxatives should not be taken while performing enemas, as they may result in extreme discomfort and possible damage to the bowels.

Limitations and Caveats

Although a great deal of clinical research has been conducted on the use of different types of enemas, there are still drawbacks. Most of the clinical data and published papers come from before 2000, and updated research has not been conducted with new experimental designs. Additionally, aside from the barium contrast enema, many lingering questions in the medical community remain on whether or not enemas are fully effective and safe.

User Experiences

The opinions expressed in this section are solely those of enema users who may or may not have medical or scientific training. Their reviews do not represent the opinions of SelfHacked. SelfHacked does not endorse any specific product, service, or treatment.

Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare providers because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

One user suffered from eight years of IBS. Already taking co-codamol every day for the last 3 years, the user tried a salt water enema in desperation after watching a YouTube video. The user reported now only occasionally taking co-codamol, and using a fleet enema 2 or 3 times a week, which provided him with immense relief.

Another user used a fleet enema in preparation for a sigmoidoscopy. The user reported it was extremely painful, made them sick to their stomach for hours, and caused them to suffer from chills, shakes, increased heart rate and cramping even after bowel emptying.

An 18-year-old with chronic constipation shared a more mixed review. The user found out about fleet enemas and decided to give it a chance since it was very affordable. Although he found it to be extremely uncomfortable, it worked within minutes and cleaned out his whole colon. The user reported to be very sore and shaky, but finds it much more bearable than the constipation, cramping, and bloating previously experienced.

About the Author

Carlos Tello

Carlos Tello

PhD (Molecular Biology)
Carlos received his PhD and MS from the Universidad de Sevilla.
Carlos spent 9 years in the laboratory investigating mineral transport in plants. He then started working as a freelancer, mainly in science writing, editing, and consulting. Carlos is passionate about learning the mechanisms behind biological processes and communicating science to both academic and non-academic audiences. He strongly believes that scientific literacy is crucial to maintain a healthy lifestyle and avoid falling for scams.


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