The main medical usages of enemas are:
* As a bowel stimulant, not
unlike a laxative, the main difference being that laxatives are
commonly thought of as orally administered while enemas are
administered directly into the rectum, and thereafter, into the
colon. Their use has been replaced in most
professional healthcare settings by oral laxatives and laxative
suppositories. In-home use of enemas for constipation and
alternative health purposes is somewhat harder to measure.
* Bowel stimulating enemas usually consist of water, which works
primarily as a mechanical stimulant, or they may be made up of water
with baking soda (sodium bicarbonate) or water with a mild hand soap
dissolved in it; buffered sodium phosphate solution, which draws
additional water from the bloodstream into the colon and increases
the effectiveness of the enema which often can be rather
irritating to the colon, causing intense cramping or "griping," or
mineral oil, which functions as a lubricant and stool softener, but
which often has the side effect of sporadic seepage from the
patient's anus which can soil the patient's undergarments for up to
24 hours. Other types of enema solutions are also used, including
equal parts of milk and molasses heated together to slightly above
normal body temperature. In the past, castile soap was a common
additive in an enema, but it has largely fallen out of use because
of its irritating action in the rectum and because of the risk of
chemical colitis as well as the ready availability of other enema
preparations that are perhaps more effective than soap in
stimulating a bowel movement. At the opposite end of the spectrum,
an isotonic saline solution is least irritating to the rectum and
colon, having a neutral concentration gradient. This neither draws
electrolytes from the body as can happen with plain water nor
draws water into the colon, as will occur with phosphates. Thus, a
salt water solution can be used when a longer period of retention is
desired, such as to soften an impaction.
* Cleansing the lower bowel prior to a surgical procedure such as
sigmoidoscopy or colonoscopy. Because of speed and supposed
convenience, enemas used for this purpose are commonly the more
costly, sodium phosphate variety often called a disposable enema.
A more pleasant experience preparing for testing procedures can
usually be obtained with gently administered baking soda enemas;
cleansing the lower bowel for colonoscopy and other bowel studies
can be effectively achieved with water based, or water with baking
soda, enema administration.
* The administration of substances into the bloodstream. This may
be done in situations where it is undesirable or impossible to
deliver a medication by mouth, such as antiemetics given to reduce
nausea (though not many antiemetics are delivered by enema).
Additionally, several anti-angiogenic agents, which work better
without digestion, can be safely administered via a gentle enema.
Medicines for cancer, for arthritis, and for age-related macular
degeneration are often given via enema in order to avoid the
normally functioning digestive tract. Interestingly, some
water based enemas are also used as a relieving agent for Irritable
Bowel Syndrome, using cayenne pepper to squelch irritation in the
colon and rectal area. Finally, an enema may also be used for
hydration purposes. See also route of administration.
* The topical administration of medications into the rectum, such
as corticosteroids and mesalazine used in the treatment of
inflammatory bowel disease. Administration by enema avoids having
the medication pass through the entire gastrointestinal tract,
therefore simplifying the delivery of the medication to the affected
area and limiting the amount that is absorbed into the bloodstream.
* General anesthetic agents for surgical purposes are sometimes
administered by way of an enema. Occasionally, anesthetic agents are
used rectally to reduce medically-induced vomiting during and after
surgical procedures, in an attempt to avoid aspiration of stomach
* A barium enema is used as a contrast substance in the
radiological imaging of the bowel. The enema may contain barium
sulfate powder, or a water-soluble contrast agent. Barium enemas are
sometimes the only practical way to "view" the colon in a relatively
safe manner. Following barium enema administration, patients often
find that flushing the remaining barium with additional water,
baking soda, or saline enemas helps restore normal colon activity
without complications of constipation from the administration of the
In certain countries such as the United States, customary enema
usage went well into the 20th century; it was thought a good idea to
cleanse the bowel in case of fever; also, pregnant women were given
enemas prior to labor, supposedly to reduce the risk of feces being
passed during contractions. Under some controversial discussion,
predelivery enemas were also given to women to speed delivery by
inducing contractions. This latter usage has since been largely
abandoned, because obstetricians now commonly give pitocin to induce
labor and because women generally found the procedure unpleasant.
Many home-given enemas are pre-packaged sodium phosphate solutions
in single-use bottles sold under a variety of brand names, or in
generic formats. These units come with a pre-lubricated nozzle
attached to the top of the container. Some enemas are administered
using so-called, disposable bags connected to disposable tubing,
although in contrast to their product names, such units can commonly
be used for many months or years without significant deterioration.
Patients who want easier, more gently-accepted enemas often purchase
Jon Dodd Enema Syringes which are commonly referred to as "Doddsys"
syringes, and which can also be used as old-fashioned hot water
bottles, to relieve aches and pains from gentle, heat
administrations to parts of the body.
For home use, disposable enema bags or bottles are common, but
reusable rubber or vinyl bags or enema bulbs may also be used.