The Real Facts on Diarrhea

Diarrhea blog for october 2020

“Diarrhea” may be one of the most misused terms by patients, second only to “migraines.” Patients will often complain of “diarrhea” when the stool is not as formed or when there is an increased frequency of bowel movements. When medical professionals are using the term diarrhea, they are referring to the liquid stool, which may be related to an increase in bowel frequency. It is an excess of stool water. Diarrhea is a symptom and not a disease. There are abundant diseases that are manifested as diarrhea.

The digestive tract (intestines and colon) absorbs 99% of the liquid ingested and secreted by your salivary glands: stomach, liver, and pancreas. On average, this is 9-10L of liquid a day. When functioning properly, the small intestines can absorb up to 10-12L of fluid, and the colon can absorb 6-8L of fluid. That’s almost 5 gallons of fluid a day – if needed! Diarrhea occurs when there is a disruption in this process.

Diarrhea can be divided into three main categories: osmotic, secretory, and complex.

Osmotic diarrhea 

Osmotic diarrhea is due to the ingestion of poorly absorbed substances: sugars, sugar alcohols, or medications. These substances will draw water into the GI tract leading to the excess of fluid in the GI tract. A very common type of osmotic diarrhea is lactose intolerance. The lactose sugar cannot be absorbed causing diarrhea. Avoiding these substances or fasting will usually resolve diarrhea.

Secretory diarrhea 

Secretory diarrhea is due to the secretion of chloride or bicarbonate, or poor absorption of sodium. A very common cause of secretory diarrhea is infection. Infectious agents affect the receptors in the intestines, causing this abnormal secretion. Fasting does not affect diarrhea in this situation.

Complex Diarrhea

It would be great if diarrhea was limited to pure osmotic or secretory causes, but unfortunately, the majority of causes of diarrhea are a combination of several different mechanisms. This can be caused by hormones, the immune system, and neural changes. As an example, inflammatory bowel disease, irritable bowel syndrome, malabsorptive syndromes, and pancreatic insufficiency.

Evaluation of diarrhea can be done by your gastroenterologist. A detailed history will often yield a differential smaller diagnosis, which can further be classified by lab work, stool testing, and or endoscopic evaluation.

Feces factoids:

  • The stool is mainly made up of water, bacteria, undigested food products, fats, and proteins.
  • Common medications that can cause diarrhea are antibiotics, PPIs (omeprazole, etc), metformin, ACE inhibitors, beta-blockers, Lasix, Synthroid, alcohol, and ibuprofen.
  • Worrisome features of diarrhea: Prolonged course, significant pain, weight loss, fevers or chills, bleeding, fatigue, and weakness
  • Antibiotics can be used to treat diarrhea, but can also cause diarrhea like Clostridium difficile colitis.
  • Stool color has to do with the types of foods eaten, time of transit through the digestive tract, and the type of bacteria in the GI tract. Green, yellow, and brown are all normal colors.  White, black, or red bloody stools are worrisome colors.


If you suffer from any of the symptoms mentioned above, we want to hear from you.

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Christopher Jue is a gastroenterologist at Digestive Health Specialists, serving Kernersville and Advance, NC.
By: Dr. Christopher Jue
Board-certified gastroenterologist at Digestive Health Specialists.
He works at our Kernersville and Tanglewood locations. 
Learn more about him here:

Digestive Health Specialists, PA is here to help if you, or someone you know, would like more information, or if you are experiencing any digestive health symptoms and would like further evaluation. Feel free to give us a call at 336-768-6211 or fill the form below.

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