If an enema doesn’t produce a bowel movement within about an hour, don’t immediately repeat it. Most enemas work within 15 minutes, and some types take up to an hour. But if nothing has happened within that window, it usually means the stool is too hard or too high up in the colon for the enema fluid to reach it. The good news is there are several next steps that can help.
Why an Enema Can Fail
The most common reason is that the stool has become extremely hard and dry, forming a mass too dense for the enema liquid to soften or move. This is called fecal impaction, and it happens after prolonged constipation. If the impacted stool is low in the rectum, an enema should theoretically reach it, but the mass may simply be too large or solid for one dose of fluid to break up.
The blockage may also be higher up in the colon. A standard enema only reaches the lower portion of the large intestine. When stool is impacted further upstream, the enema fluid never contacts the blockage at all. In rarer cases, a structural problem like a narrowing of the colon or a twist in the bowel (called a volvulus) can prevent stool from passing regardless of what you put in from below.
Technique matters too. Lying on your left side with your knees drawn toward your chest positions the enema tip to flow naturally into the lower colon. If you were standing, sitting on the toilet, or lying on your right side, the fluid may not have reached where it needed to go. Expelling the liquid too quickly, before it has time to soften the stool, can also lead to a failed attempt.
What to Do in the Next Few Hours
Do not use a second dose of the same enema within 24 hours. This is especially important for sodium phosphate enemas (the most common drugstore type). The FDA has issued warnings that exceeding the recommended single dose of these products can cause dangerous shifts in your body’s electrolyte levels, potentially leading to kidney injury, heart rhythm problems, and in extreme cases, death. Even if nothing came out, one dose in 24 hours is the limit.
Instead, try an oral approach. An osmotic laxative like polyethylene glycol (sold as MiraLAX and generics) works by pulling water into the stool from the inside, softening it throughout the colon rather than just at the bottom. This is the recommended option when the blockage may be higher up. Magnesium-based options like milk of magnesia or magnesium citrate also draw water into the bowels and can trigger a movement, sometimes within a few hours. These oral laxatives reach stool that an enema simply cannot.
While you wait for the laxative to work, drink plenty of water. Dehydration makes stool harder and makes osmotic laxatives less effective, since they depend on available fluid to do their job. Light movement like walking can also help stimulate the bowel.
Who Faces Higher Risks
Certain people should be especially cautious about repeating enemas or self-treating a failed one. The FDA specifically flags adults older than 55, anyone with kidney disease, people who are dehydrated, and those with bowel obstruction or inflammation as being at higher risk for complications from sodium phosphate products. If you fall into any of these groups, contact a healthcare provider rather than trying additional treatments on your own.
Young children are also vulnerable. Their smaller bodies are more sensitive to electrolyte shifts, and a failed enema in a child warrants a call to the pediatrician rather than a second attempt at home.
When the Problem Needs Medical Help
If an oral laxative also fails to produce results within a day, the constipation is likely severe enough to need professional intervention. A provider can take an abdominal X-ray to see exactly where the stool is stuck and how much has built up. That imaging changes the treatment plan: low impaction may respond to a medically supervised enema with a larger volume, while high impaction typically calls for a prescription-strength oral solution.
For the most stubborn cases, a provider may perform a manual disimpaction, which involves physically breaking up and removing the hardened stool from the rectum with a gloved finger. This is typically reserved for people with fecal impaction that hasn’t responded to other therapies, or those with conditions like pelvic floor dysfunction that prevent normal bowel movements. Only a trained medical professional should do this. Attempting it yourself risks tearing the rectal lining or causing other injury.
Warning Signs That Need Immediate Attention
A failed enema on its own is not an emergency, but certain symptoms alongside it are. Severe abdominal pain, especially if it’s sudden or localized to one area, could indicate a bowel obstruction or perforation. Vomiting, a visibly swollen and rigid abdomen, or fever alongside constipation also warrant urgent care.
If you used a sodium phosphate enema and then notice drowsiness, sluggishness, a sharp drop in how much you’re urinating, or swelling in your ankles, feet, or legs, these are signs of kidney injury from electrolyte imbalance. Seek medical attention right away and do not take another dose of the product.
Preventing Repeat Failures
If you’re reaching for enemas regularly, the underlying constipation needs a longer-term solution. Chronic use of enemas can make the bowel increasingly dependent on stimulation to move, creating a cycle where natural motility decreases over time. A daily osmotic laxative like polyethylene glycol is generally considered safer for ongoing use than repeated enemas, because it works with the body’s own fluid balance rather than forcing mechanical stimulation.
Increasing dietary fiber gradually (aiming for 25 to 30 grams per day), staying well hydrated, and building regular physical activity into your routine address the root cause for many people. For those with a structural or neurological reason for chronic constipation, a gastroenterologist can identify the specific problem and match it with targeted treatment.