Seeing undigested pills in your stool can be normal for certain types of medication and doesn't necessarily mean there is something wrong with your digestive tract.
However, it could be a concern in some instances, such as impaired intestinal absorption or abnormal gastrointestinal (GI) motility. Gelatin Capsule Sizes
This article discusses why pills may be in your stool and when to be concerned.
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.
Extended-release medications are slowly released into the body over a period of 12 to 24 hours.
The outer coating or shell of these medications is made of either gelatin (hard or soft) that comes from animal collagen or cellulose, a plant-based fiber.
In most cases, the body's digestive acids break down the outer shell, but not always. In some cases, the shell will remain intact and be expelled from the body largely intact. But, while it may seem like the medication has not been absorbed, it has.
These extended-release medications where the shell has been left behind are sometimes referred to as "ghost pills" or "ghost tablets," meaning there is only the outer shell of a pill with no active ingredients remaining.
It is similar to the digestion of corn kernels, where the inner grain is absorbed but the outer shell that is made of cellulose passes through undigested in the 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 medication for diabetes and your blood sugar remains normal, there is a good chance the medication is getting absorbed properly.
When in doubt, talk to your healthcare provider. They can tell you if this is a common situation for the particular medication and prescribe an alternate drug if needed.
Medications that may show up as ghost pills include:
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 all of the 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.
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.
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, talk to 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 healthcare provider know if you find undigested medications in your stool. It may not be a serious concern but will likely be something your healthcare provider will want to check out.
Mir F, Achakzai I, Ibdah JA, Tahan V. Undigested pills in stool mimicking parasitic infection. Case Rep Gastrointest Med. 2017;2017:3718954. doi:10.1155/2017/3718954
Prakash A, Soni H, Mishra A, Sarma P. Are your capsules vegetarian or nonvegetarian: An ethical and scientific justification. Indian J Pharmacol. 2017 Sep-Oct;49(5):401-404. doi: 10.4103/ijp.IJP_409_17
Tungaraza TE, Talapan-Manikoth P, Jenkins R. Curse of the ghost pills: The role of oral controlled-release formulations in the passage of empty intact shells in faeces. Two case reports and a literature review relevant to psychiatry. Ther Adv Drug Saf. 2013;4(2):63–71. doi:10.1177/2042098612474681
Yuan X, Zhao J, Wu X, et al. Extraction of Corn Bract Cellulose by the Ammonia-Coordinated Bio-Enzymatic Method. Polymers (Basel). 2022 Dec 31;15(1):206. doi: 10.3390/polym15010206
International Foundation for Gastrointestinal Disorders. Motility disorders.
NIH Office of Dietary Supplements. Dietary supplements: What you need to know.
Gupta S, Kesarla R, Omri A. Formulation strategies to improve the bioavailability of poorly absorbed drugs with special emphasis on self-emulsifying systems. ISRN Pharm. 2013;2013:848043. doi:10.1155/2013/848043
By Julie Wilkinson, BSN, RN Julie Wilkinson is a registered nurse and book author who has worked in both palliative care and critical care.
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