Concerned About Undigested Pills in Stool?

There are times when you might look into the toilet after a bowel movement and see a pill or tablet only partially digested. People who see this might wonder if something is wrong with their digestion or if a medication is working like it's supposed to.

However, seeing undigested drugs in your stool doesn't necessarily mean that there is anything wrong with your digestive tract. Learn why this may occur and when to discuss it with your healthcare provider.

Potential Causes of Undigested Pills in Stool

Nusha Ashjaee / Verywell

Drug Coatings and Shells

Drug companies make many different types of coatings to ensure that a drug dissolves when it is supposed to and at the correct rate for the drug to work. These include tablets marked "extended-release" or "sustained-release" as well as capsules that contain the active drug in a powdered or pellet form.

In most cases, the body's digestive acids will break down the outer shell, but not always. This is especially true with certain capsules. In some cases, the shell will remain intact and be expelled from the body largely intact. But, while you may think the medication has not been absorbed, it actually has.

It is similar to the digestion of corn kernels, where the inner grain is absorbed but the tough fibrous husk passes through into stool.

The best way to tell if a drug has been absorbed is to poke around in your stool and check if the shell contains any traces of medication.

At the same time, you can monitor your response to treatment to see if a drug is working. For instance, if you are taking medications for diabetes and your blood sugar remains normal, there is a good chance the medications are getting absorbed properly.

When in doubt, talk to your healthcare provider. They can tell you if this is a common situation and prescribe an alternate drug if needed.


Extended-release capsules have a special outer coating designed to be absorbed slowly. Although the active drug may be released, the shell can sometimes pass through only partially digested.

Absorption Problems

In rare cases, there may be gastrointestinal motility problems that prevent a drug from being properly absorbed. Motility refers to the muscle contractions that move food and other substances through the intestines. If the contractions are too fast, referred to as rapid dysmotility, a tablet or capsule may pass through the intestines undigested.

Diarrhea is a common example of this. Causes may include:

Some of these conditions, like celiac disease, also cause malabsorption in which the intestines are less able to absorb nutrients and medications. If you are not absorbing your medications properly, then there is a good chance you are also not getting nutrients from your food either.

Medications may come out of the body undigested if the intestines contract faster than normal. When this occurs, nutrients and drugs may pass through the digestive tract unabsorbed.

Improper Medication Use

While it is unlikely that taking a drug in the wrong way can cause it to be unabsorbed, it is possible. Medications work in a very specific way and must be taken as prescribed to ensure that they are broken down and absorbed as they're supposed to be .

For example:

  • Certain drugs cannot be taken together due to interactions that either increase or decrease the rate of absorption.
  • Certain drugs require a large or high-fat meal to be absorbed.
  • Some drugs may not be absorbed properly if taken with food.
  • Drug absorption may be affected when taken with specific foods, such as grapefruit juice.

Even so, the lack of absorption is usually "invisible" and will not cause a pill or capsule to be excreted in stool intact.

If you're not sure you are taking a drug correctly, ask your doctor or pharmacist.


There are many reasons why a pill or capsule may appear undigested. It could be that the capsule has not broken down fully, though the active drug may have been absorbed. Or, you may have diarrhea or another disorder that causes a drug to pass through the intestines too quickly. Or, you could simply be taking the drug incorrectly.

Whatever the cause, let your doctor know if you find undigested medications in your stool. It may not be a serious concern but will likely be something your doctor will want to check out.

7 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.
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By Julie Wilkinson, BSN, RN
Julie Wilkinson is a registered nurse and book author who has worked in both palliative care and critical care.