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 your lower bowel [R].

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 Enema’s Used For?

Some people may feel uncomfortable by the thought of an enema. However, it is very 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

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 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

Coffee enemas stimulate the release of bile, which when released by the liver into the intestines helps digest food. In a pilot study of 34 patients (who needed an endoscopy), those treated with a coffee enema had better imaging results than those patients who didn’t. Additionally, no adverse effects were found in any of the patients who were given a coffee enema [6].

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. They may also cause health complications without medical supervision [1, 2].

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) [7].

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 [8, 9].

Mineral Oil Enema

Mineral oil enemas are used to treat constipation and to clean out your intestines and digestive organs such as your colon (gastrointestinal tract). For older adults, this type of enema is more recommended than fleet enemas. Its use with fleet enema has also been reported to help remove large tar burns [10, 11].

Mechanism of Action

The general mechanism of enemas causes increased pressure and potential irritation of the external tissue in your bowels and anus. This pressure and irritation may potentially cause harmful effects, but if used correctly, enemas are proven to be safe [12].

Phosphate Enema

Phosphate enemas (one type of fleet enema) cause stimulation of the external tissue in your bowels. This solution is more concentrated than the layer below the external tissue (hypertonic solution), and this results in the movement of water between the tissue. That causes the stimulation and pressure changes, which ultimately help bowel movements [12].

Salt Water, Tap Water, and Soap Suds Enema

These types of enema solutions also increase pressure in your bowels, promoting evacuation. When used in small volumes, these enemas are less irritating than phosphate enemas [12].

Mineral Oil Enema

Commonly composed of glycerin, this enema causes water movements (osmosis) within your bowels that promotes defecation [12].

How to Use an Enema

1) Relieves 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 [10].

Enemas are an effective procedure to treat constipation. Although the most common treatments are laxatives, enemas are just as useful. A variety of enema treatments are available, and each of them has characteristics that help in specific cases [13].

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 immediately results in relief [13].

In 512 children with constipation (retrospective cross-sectional study) treated with an enema of small volume soap suds, more than 80% showed positive results without any complications. In an additional study (descriptive and prospective) on 79 children with from constipation, salt water enema treatment resulted in 62% of the children reporting relief [4, 14].

In another study (retrospective study), 214 patients with constipation were treated with only a milk and molasses enema in the emergency department. Bowel evacuation in these patients was 87.9%, and 82.4% successful when used after other treatments failed [15].

2) Cleanses the Colon

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, this can lead to more serious problems such as chronic diseases. Cleansing your colon may minimize the risk of the development of complications.

Additionally, 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 [16].

In one study (RCT) 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 the patients’ 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 [17].

A group of 123 patients( cross-sectional study) who also required a barium X-ray were given cleansing enemas to clean their colon. Patients who completed more rounds of enema were found to have significantly less fecal matter present in their bowels [18].

Although there is a widespread practice of colonic cleansing, investigators report that its use to improve and promote health is not supported or recommended in the published scientific literature [19].

3) Helps 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 [8].

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 [20].

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 and that the colonoscopy may have technical difficulties. They concluded that both techniques are beneficial for visualization, with each having their own drawbacks [21].

In a study of 103 patients (prospective study) who just received an incomplete colonoscopy, subsequently received a barium enema. Of these, the barium enema revealed the entire colon of 94% of the patients. Additionally, this technique allowed the detection of abnormalities in 14 patients that were not found in the colonoscopy [20].

Barium enema visualization is best used to detect bulges in the wall of the large intestines (diverticular disease). These 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) [21, 22].

4) For Drug Administration

Enemas can be used to administer drugs through the rectum. This method of drug administration is very 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 of this is being able to maximize local drug concentrations in the colon [23].

Two of the most commonly used types of enemas for drug administration is sucralfate enemas and vancomycin enemas. Sucralfate is frequently used to treat gut diseases, and vancomycin is an antibiotic [24, 25].

In one study, 22 patients with inflamed colons (cross-sectional study) were given sucralfate enemas twice a day for 3 weeks. Afterward, 19 of the 22 patients demonstrated clinical improvements. Additionally, 6 patients with rectal ulcers (cross-sectional study) were treated with sucralfate retention enemas for 6 weeks. Four of the patients had complete relief of symptoms, while the other 2 experienced marked improvements [26, 27].

A retrospective chart review of 47 patients with severe colon infections (Clostridium difficile colitis) was treated with a colonic vancomycin enema. Seventy percent of the patients responded with full recovery and thus did not require surgery [28].

5) May Help Remove of Tar Burns

There is a case study of an individual who suffered tar burns throughout his body. The use of a mineral oil enema facilitated application into difficult areas, with the mineral oil proving to be an effective agent of removal of all the tar burns [11].

Side Effects

There are a variety of different side effects associated with different types of enemas. The 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 [29, 30,].

It is critical that a patient using phosphate enemas promptly evacuates, because electrolyte disturbances (hyperphosphatemia) may be life-threatening [12, 31].

Cleansing enemas are effective but can perforate and damage the bowels. In an experiment (double-blind design) with 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, 31].

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 [32].

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 encountered 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 a study (retrospective study) of 160 premature babies who received contrast enemas during intensive care, 21 were reported to have clinical sepsis [33].

Kidney failure is prevalent among elderly 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 which died as a result [34].

There have been associations found between HIV incidence and men who have recently used enemas. In one report, over 95% of HIV-positive MSM in their sample used an enema before anal sex and 45.8% used an enema after anal sex [35].


Given the effect of fleet enemas on your kidney, electrolytes, and bowels, there may be some interactions with other drugs you are taking [29, 34, 3].

Most painkillers (i.e., ibuprofen) put a strain on your kidney 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 [36].

Additionally, since enemas stimulate bowel movements, most drugs are 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 [37].

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

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 now only occasionally takes co-codamol, and uses a fleet enema 2 or 3 times a week, which has been providing him with immense relief.

Another user used a fleet enema in preparation for a sigmoidoscopy. It was reported to be 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 submitted 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 constipation, cramping, and bloating previously experienced.

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