Diarrhea After Colonoscopy or Prep: Treatments & When It’s Serious

Key takeaways:

• The purpose of a colonoscopy bowel prep is to fully and rapidly cleanse the bowels, typically resulting in diarrhea.
• Post-procedure diarrhea is a common occurrence after having a colonoscopy and typically resolves within a week.
• Simple dietary changes and over-the-counter supplements may aid in a quicker resolution of diarrhea after a colonoscopy.

After a colonoscopy, it is not uncommon for patients to report experiencing abdominal discomfort, nausea, vomiting, and diarrhea. While diarrhea is generally temporary, it can lead to some confusion, particularly after completing the colonoscopy prep which presumably cleared the bowels completely.

Understanding what is normal and what might be cause for concern can help you decide if a follow-up with your healthcare provider is necessary. This article will explain why diarrhea occurs after a colonoscopy, how long it typically lasts, and when you should be concerned.

Is it normal to have diarrhea after a colonoscopy or colonoscopy prep?

Diarrhea is an expected outcome of colonoscopy prep but is also a common symptom experienced after undergoing the procedure itself. It is reported that anywhere from 24%-32% of patients will experience minor post-procedure complications such as abdominal pain, bloating, and diarrhea that typically resolve within 7 days.

Typical duration of diarrhea after a colonoscopy or colonoscopy prep

The duration of diarrhea after a colonoscopy varies depending on several factors, including the type of preparation used, the individual's underlying health, and whether or not something such as a biopsy was performed during the procedure.

In most cases, diarrhea can be expected for 1-3 days following the procedure but it is not unusual for some patients to experience mild diarrhea for up to a week.

Causes of diarrhea after a colonoscopy or colonoscopy prep

To a certain degree, diarrhea after colonoscopy prep and a colonoscopy is to be expected. The main purpose of a colonoscopy prep is to completely clear out the colon so that it can be clearly visualized during the procedure. Below are the most likely reasons for diarrhea to occur.

Bowel prep side effects

The bowel preparation process involves using medications that are meant to stimulate the bowels and clean out the colon so that the provider performing the colonoscopy can fully visualize the colon.

These medications work by rapidly flushing out the intestines and the rapid transit time can lead to diarrhea.

Post-procedure side effects

A common cause of diarrhea after a colonoscopy is the temporary disruption of bowel function.

Colonoscopies involve manipulating the intestines, which may cause irritation, inflammation, and an increase in bowel motility. For some patients, this can trigger symptoms such as diarrhea and bloating.

Infection

Infection is always a potential risk associated with any type of procedure. Studies have found that the risk of infection after a colonoscopy is fairly low, especially compared to other gastrointestinal procedures such as endoscopy, but there is still a risk nonetheless.

If you are experiencing diarrhea for more than a week or have any other symptoms such as fever, chills, and body aches, infection should be considered and you should speak with your healthcare provider immediately.

Read our guides on different types of diarrhea and common causes of diarrhea for more.

How to get relief from or stop diarrhea after a colonoscopy or colonoscopy prep

The entire purpose of a colonoscopy prep is to flush out the bowels completely, and therefore diarrhea is to be expected. Diarrhea after a colonoscopy is also common and typically lasts for a few days but there are a few things you can do to find relief from this symptom post-procedure.

BRAT diet

The BRAT diet consists of bananas, rice, applesauce, and toast. In addition to easing diarrhea by promoting more formed and solid stools, the BRAT diet can also help with associated symptoms such as nausea and vomiting.

If you are still experiencing significant diarrhea after consuming a BRAT diet for 48 hours, or experiencing diarrhea in general for more than 7 days after a colonoscopy, you should consider speaking with your healthcare provider.

Rehydrate

Whether diarrhea is caused by an infection, diet, or by medications and procedures such as bowel prep medications and colonoscopies, it can lead to dehydration.

Increasing hydration by drinking plenty of water and fluids containing electrolytes is a critical step in preventing dehydration whenever you experience diarrhea.

Probiotics

Probiotics can be used for both the prevention and treatment of diarrhea. Probiotics can help regulate an imbalance of intestinal bacteria that may contribute to diarrhea, particularly after the bowel disruption that occurs with a colonoscopy.

While there are an overwhelming amount of different probiotics that can be found on the shelves of pharmacies, research shows that Saccharomyces boulardii and Lactobacillus reuteri are the two most effective types at reducing diarrhea.

Read our full guide on treating diarrhea for more.

When you should see a doctor for diarrhea after a colonoscopy or colonoscopy prep

Diarrhea that has no additional associated symptoms and resolves within 7 days of the procedure is generally not a reason to consult your doctor.

However, while a few days of diarrhea after the procedure itself is normal, there are some symptoms that should prompt you to see your healthcare provider.

You should see a doctor if:

• Diarrhea persists for more than a week.
• You are experiencing abdominal pain or cramping or rectal pain for more than a few days.
• You have signs of dehydration, such as dry mouth, dizziness, or dark urine.

You should go to the emergency room if:

• You experience severe, persistent abdominal pain or bloating.
• You are experiencing a fever after the procedure.
• You notice dark, or black tarry stools or a large amount of blood in the stool.

Questions to ask your doctor about diarrhea after a colonoscopy

• Is it normal to experience diarrhea after a colonoscopy?
• How long should I expect my diarrhea to last after having a colonoscopy?
• Are there any medications or dietary changes that can help reduce or improve my symptoms?
• What would be a sign of abnormal diarrhea after a colonoscopy?

How a doctor can help treat diarrhea after a colonoscopy

Much of what a doctor will recommend for diarrhea after a colonoscopy is similar to what you can achieve on your own at home. Make sure to let your doctor know if you are experiencing diarrhea for more than a week after your colonoscopy.

Dietary recommendations

Diet can significantly help reduce diarrhea. Allowing the bowels to rest completely for the first 24 hours by consuming a clear liquid diet and then advancing as tolerated is the general recommendation when experiencing diarrhea.

As the diet is advanced, you should stick to bland and easily digestible foods as well as foods that can help solidify the stool such as eggs, bananas, apples, boiled potatoes, and lean proteins. Dairy and high fiber containing foods should be avoided.

Fluids

As previously mentioned, staying hydrated when experiencing diarrhea is extremely important.

Your provider will recommend increasing your fluid intake and consuming oral rehydration solutions. If you are unable to tolerate oral fluids, they may recommend IV fluids.

Frequently asked questions: diarrhea after a colonoscopy

Prior to taking any medications or undergoing any type of medical procedure, you should make sure to have all of your questions answered. Here are the most common questions about diarrhea that may be experienced with a colonoscopy prep and after the procedure.

What if you’re experiencing diarrhea for a week or longer after a colonoscopy?

While mild diarrhea may persist for a few days after a colonoscopy, diarrhea lasting longer than a week warrants medical evaluation.

Although rare, there is always a risk for procedural complications, trauma, and infection to occur as a result of a colonoscopy that will require intervention from a healthcare provider.

Can you take anti-diarrhea medication or imodium after a colonoscopy?

There are actually some studies that recommend taking imodium after completing a bowel prep and prior to a colonoscopy.

The reason behind this is that medications like imodium can slow the passage of bile into the bowels, giving a clearer view of the colon. Information on whether you can take anti-diarrheal medication for diarrhea after a colonoscopy is less clear and may vary based on the circumstances and practices of your healthcare provider. You should discuss this directly with the provider who performed your colonoscopy before taking medications like imodium.

What if your diarrhea changes consistency or color after a colonoscopy?

Due to bowel prep medications and the manipulation of the bowels that occur during the procedure, stool consistency may be softer or more liquid in consistency for a few days.

Many patients also report an increase in mucus in their stool after a colonoscopy. As long as stool returns to normal within a week, these changes are not reasons for concern. Changes in stool color should be taken more seriously. If your stools appear dark or tarry black, this indicates the presence of digested blood and warrants immediate evaluation.

The presence of bright red blood in your stool can also indicate trauma and possible perforation of the bowels as a result of the procedure and should be evaluated promptly.

Navigating colonoscopy associated diarrhea

As if the prep for a colonoscopy isn’t unpleasant enough, having to experience continued diarrhea after the procedure sounds downright unfair. Understanding that this is a common and expected symptom that usually resolves quickly will hopefully make the whole experience a bit more tolerable. Remember that if you are experiencing diarrhea for more than a week after your colonoscopy, you should follow up with your provider.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Lane Thaut, DO.

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