Causes of Loose Stool

Causes of Loose Stool

Woman looking worried.
Jamie Grill/The Image Bank/Getty Images

It can be worrisome when you start to see a change in the way that your bowel movements look. Loose stools could be the result of some not-so-serious lifestyle change or could be a symptom of a more serious illness. Typically loose stools are experienced along with the urgency and frequent bowel movements of diarrhea (but not always!), and thus typically the causes of loose stool may be the same as the causes of diarrhea. This overview will educate you as to some of the more common causes of loose stools.

Note: Any change in bowel habit, including a change to loose stools, that lasts longer than two weeks, should be brought to the attention of your physician for proper diagnosis and treatment.

The Science Behind Loose Stools

digestive system illustration
Your large intestine is where stools are formed. Images

A Quick Digestion Review

To help you to understand why your body is producing loose stools, it helps to refresh your memory as to how the digestive system works. In a nutshell, the food that we eat is first broken down in our stomachs, then sent to our small intestines, where nutrients are absorbed. The small intestine then sends the undigested fiber along with water into our large intestine where the water is drawn out to form stool.

Loose stool is a reflection of too much water in the stool. This excessive water could be the result of the stool moving too quickly through the large intestine so that adequate amounts of fluid do not have time be be absorbed back into the body. Loose stool may also be the result of the fiber in the fecal matter drawing too much water into itself through osmosis. Last, loose stool could be the result of the intestine secreting too much liquid into the existing fecal matter. Any or all of these conditions may be in place, for various reasons, with the end result that you are now experiencing loose stool.

Anything New In Your Life?

stressed woman at work
Stress can lead to looser stools. Cultura RM/Jason Butche/Collection Mix: Subjects/Getty Images

As you try to figure out what might be going wrong, and to make sure that you give your doctor information that will be helpful for a correct diagnosis, ask yourself the following questions:

  • Any recent changes in the way you eat?
  • Are you on a new medication?
  • Has your water source changed, exposing you to different types of bacteria?
  • Have you recently traveled?
  • Have you recently experienced food poisoning or some other intestinal illness?
  • Has your stress level been higher than usual?

Dietary Causes

fruit salad being served
Too much fruit can loosen up your stools. Rosemary Weller/The Image Bank/Getty Images

The following foods have a reputation for contributing to loose stools. This means that having loose stools after eating these foods is typical and therefore not necessarily a sign that your loose stools are because you have a disease.

  • Sugar-free foods and chewing gums containing artificial sweeteners ending in -ol
  • Fat-free foods containing olestra
  • Fruits, when eaten in larger amounts
  • Caffeinated drinks, such as coffee, tea, and soda

Certain Medications and OTCs

various pills and capsules
Photography by ZhangXun/Moment/Getty Images

Sometimes the reason for a change in your stool has to with a new medication or over-the-counter product you may be using. The following medications can result in loose stools:

  • Antacids containing magnesium
  • Antibiotics
  • Cancer chemotherapy drugs
  • Over-the-counter headache medications
  • Laxatives
  • Vitamin formulations containing magnesium

Diseases and Disorders

woman doctor with male patient
There are many medical problems that cause loose stools. Dan Dalton/Caiaimage/Getty Images

There are a wide variety of health conditions that have loose stools as a symptom. Below you will find some of the more common diseases and disorders that your doctor will be considering as they try to figure out why you are experiencing a change in your bowel habits.

The following health conditions related to food intake may contribute to loose stools:

Although the following conditions are very different in terms of causation, they share the symptom of loose stools:

Symptoms Requiring Immediate Medical Attention

woman taking her temperature
Seek medical attention for any severe symptoms. Sam Edwards/OJO Images/Getty Images

As you can see, the causes of loose stool can range from a mild reaction to a food eaten to a more serious acute or chronic illness. If you are experiencing any of the following symptoms alongside your loose stools, it is imperative that you contact a medical professional immediately:

  • Blood or pus in the stool
  • Dehydration
  • Fever that is higher than 102 or lasts longer than three days
  • Severe abdominal pain
  • Stool that is black or tarry
  • Unexplained weight loss


Juckett G & Trivedi R. "Evaluation of chronic diarrhea." American Family Physician 2011 84:1119.

"Diarrhea" Medline Plus Website accessed July 27, 2014.

"Diarrhea" The Merck Manual Website accessed July 21, 2014.

"Diarrhea" National Digestive Diseases Information Clearinghouse (NDDIC)

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