Paradoxical Diarrhea or Overflow Diarrhea

This type of diarrhea is really due to having constipation

It is possible to have diarrhea and constipation at the same time. This is called paradoxical diarrhea or overflow diarrhea. It happens when watery stool leaks out around hard stool in the rectum.

This article looks at paradoxical diarrhea, its causes, and treatment. It also offers suggestions for how to prevent paradoxical diarrhea.

A woman holds a hot water bottle against her abdomen as though she's in pain.
Grace Cary / Moment / Getty Images

What Causes Constipation?

If you have fewer than two or three bowel movements per week, you may have constipation. With constipation, stool tends to be hard and difficult (sometimes even painful) to pass. You may need to strain or push to have a bowel movement.

Constipation is common in children. Most adults experience it a few times a year. Constipation might last for just a few days. It could also be chronic and persist for a long period of time.

Some causes include not eating enough fiber or drinking enough water and having a low level of physical activity. Traveling or stress can also cause some people to become constipated.

Medications are also a major cause of constipation.

Some medications that may cause constipation include:

Conditions that may cause constipation include:

Colon cancer is also linked to constipation, as well as other symptoms like blood in the stool, pain, weight loss, or fatigue.

How Constipation Causes Paradoxical Diarrhea

Constipation may only last for a few days. In some cases, though, it can become chronic. When you don't pass stool for an extended period of time, it may build up in the digestive tract. This can result in what’s called fecal impaction.

Fecal impaction is when there is a large, hard mass of stool in the intestine. This condition might also be called impacted stool, impacted bowel, or impacted colon. The large intestine may respond to fecal impaction by producing fluid.

A person who has a fecal impaction may have watery stools even as some hard stools are not moving in the intestines. In fact, it might be difficult to contain the stool in the rectum, and it may leak, leading to bathroom accidents or incontinence.

This happens because there is watery stool behind the fecal impaction seeping out around the hard mass of stool. This liquid stool is often foul-smelling.

The problem is worsened when the rectum is distended (enlarged) and the internal anal sphincter muscle relaxes. This allows stool to leak out.

Causes of Fecal Impaction

Fecal impaction can occur due to chronic constipation. it is a significant problem for people who are bedridden due to chronic disease.

Chronic use of medications that cause constipation can lead to fecal impaction.

Laxatives, medicines that can help you have a bowel movement when you're constipated, can also contribute to fecal impaction.

Some types of laxatives are safe to use long-term. Others can cause dependence. This means that long-term use of certain laxatives may eventually make your body unable to have a bowel movement without them.

Laxatives that are usually safe for long-term use include:

People that are pregnant, people with electrolyte imbalances, hepatic or renal impairments, possible intestinal obstruction, ulcerative colitis, or Crohn's disease, and people who are bedridden should discuss laxatives with a healthcare provider before using them. Additionally, discuss laxatives with your child's pediatrician before providing a laxative to a child.

Stimulant laxatives and stool softeners aren't usually recommended for long-term use. Stimulant laxatives increase the movements of the muscles in the intestine. Stool softeners cause more water to be drawn into the intestine.

When these kinds of laxatives are stopped, constipation may return or get worse. Eventually, this could lead to fecal impaction.

Paradoxical Diarrhea In Children

Children may hold in bowel movements, which can lead to constipation. And when children are constipated, they may hold in bowel movements in order to avoid the pain—and this leads to more constipation. This can result in a cycle of painful bowel movements.

Encopresis is when children have bathroom accidents or soil their underwear with stool. Sometimes, soiling accidents are actually paradoxical diarrhea. So it's important for parents to know that constipation may lead to encopresis.

To avoid this, make sure children:

  • Drink enough water
  • Eat enough foods that contain fiber
  • Eat fewer foods that may contribute to constipation, like bread, bananas, rice, and cheese

If your child is soiling their underwear, your pediatrician can help you understand how to treat the problem.

Removing an Impaction

There are several different treatments that can be used to remove impacted stool.

  • Manual removal: In some cases, the hard mass of stool in the rectum can be removed manually. This means that a healthcare provider can dislodge the stool with a gloved, lubricated finger. An anoscope is a tool used to look inside the anus and to help your provider remove the stool.
  • Enema: A fecal impaction may also be removed with an enema. This might be done when the impaction is not as close to the anus. The enema may need to be given by a healthcare professional.
  • Laxative: Sometimes impacted stool may be higher in the digestive tract. If it can't be reached with an enema, laxatives might be used.

Less often, surgery to remove the fecal matter may be necessary. This is considered more often for those who have had prior surgery on the anal area. This may include surgery on anal fistulas or hemorrhoid removal.

Preventing Paradoxical Diarrhea

You can prevent paradoxical diarrhea by avoiding constipation. This may mean making diet and lifestyle changes. It can also be helpful to incorporate medical treatments if you are prone to chronic constipation, but you should discuss this with your healthcare provider.

Dietary Strategies

Drinking more water can help keep your stools soft.

To get more fiber in your diet, eat foods such as:

  • Whole grains
  • Legumes
  • Fruits
  • Vegetables
  • Nuts

At-Home Medical Treatments

Fiber supplements are bulk-forming laxatives. These may also be used to keep stools soft so they can pass easily.

Stimulant laxatives might help prevent constipation. However, it is important to ask a doctor before you take these. This is because of the risks involved in using them long-term. For short-term use, these laxatives are often safe.

If your constipation lasts more than a few days, it is important to find the cause and get proper treatment rather than keep using laxatives.

Some people also use enemas for constipation. It's important to note that long-term use of enemas can have risks. Using an enema once in a while shouldn’t be a problem. They are not a solution for chronic constipation, though.

When to See a Healthcare Provider

Diarrhea and/or constipation that comes and goes for a few days isn't usually cause for concern. See a healthcare provider, though, if you also have any of these symptoms:

  • Dehydration, which causes dry mouth and skin, and a weak, rapid heart rate
  • Blood or mucus in the stool
  • Light-headedness or dizziness
  • Increased heart rate
  • Severe abdominal pain

Constipation that goes on long enough to cause paradoxical diarrhea may need treatment. You may need to find out why you have constipation in order to stop it from happening again.

Summary

Paradoxical diarrhea is caused by fecal impaction, a hard stool that is "stuck" in the colon. Constipation that lasts for a long time may lead to fecal impaction. Sometimes, watery stool can leak around the impaction. Long-term use of stimulant laxatives or stool softeners can contribute to this problem.

A fecal impaction can be removed manually or with an enema. Rarely, surgery may be necessary. You can prevent paradoxical diarrhea by eating plenty of fiber, drinking enough water, and talking to your healthcare provider for advice about constipation. 

A Word From Verywell

It can be confusing if you have both constipation and diarrhea. In fact, constipation can actually be the cause of your diarrhea, and having loose stools doesn't necessarily mean that your constipation has resolved. Paradoxical diarrhea can even lead to leaks and accidents.

These problems won't usually resolve on their own, but treatment can get you back to having regular bowel movements, with relief of your abdominal discomfort. So talk to a healthcare provider to get help.

Frequently Asked Questions

  • Can fecal impaction cause other complications?

    Yes, more severe complications can occur if the impaction is not cleared. Impaction causes increased colon pressure. This can lead to ulcers and colon perforation, which is dangerous.

  • What are the best natural ways to avoid fecal impaction?

    You can avoid fecal impaction in the same way you avoid constipation. Eat a fiber-rich diet and drink plenty of fluids. If it's a recurrent issue, a healthcare provider may advise you to use stool softeners or laxatives. Your provider may also adjust any medications you're taking that could cause constipation.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Serrano Falcón B, Barceló López M, Mateos Muñoz B, Álvarez Sánchez A, Rey E. Fecal impaction: a systematic review of its medical complicationsBMC Geriatr. 2016;16:4. doi:10.1186/s12877-015-0162-5

  2. Hussain ZH, Whitehead DA, Lacy BE. Fecal impactionCurr Gastroenterol Rep. 2014;16(9):404. doi:10.1007/s11894-014-0404-2

  3. Harvard Medical School. Constipation and impaction.

  4. American Academy of Pediatrics. Soiling (encopresis).

  5. Obokhare I. Fecal impaction: a cause for concern? Clin Colon Rectal Surg. 2012;25(1):53-58. doi:10.1055/s-0032-1301760

  6. National Institute of Diabetes and Digestive and Kidney Diseases. Eating, diet, & nutrition for constipation.

  7. Portalatin M, Winstead N. Medical management of constipation. Clin Colon Rectal Surg. 2012;25(1):12-19. doi:10.1055/s-0032-1301754

  8. Serrano Falcón B, Barceló López M, Mateos Muñoz B, Álvarez Sánchez A, Rey E. Fecal impaction: a systematic review of its medical complicationsBMC Geriatr. 2016;16(1):4. doi:10.1186/s12877-015-0162-5

  9. Hussain ZH, Whitehead DA, Lacy BE. Fecal impactionCurr Gastroenterol Rep. 2014;16(9):404. doi:10.1007/s11894-014-0404-2

Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.