group of dehydrated people rehydrating

When your gastrointestinal condition leaves you dehydrated

Rosanna Lee, RD

Written by: Rosanna Lee, RD

Updated: September 26th, 2023

Adequate hydration is essential in supporting the body’s basic functions. Individuals with certain gastrointestinal (GI) conditions may be particularly vulnerable to dehydration, including Inflammatory Bowel Disease, diarrhea-predominate Irritable Bowel Syndrome (IBS-D), celiac disease and gastroenteritis. Other more severe conditions such as cancers affecting the gastrointestinal tract (ex: colorectal, esophageal) can lead to dehydration due to diarrhea or vomiting.

Keep reading to learn about the common causes, symptoms, and treatments for dehydration! More of a visual learner? Download our infographic!

Importance of hydration

It is estimated that about 60% of your body is made up of water, which explains why hydration is crucial to survival. Water has numerous roles which include aiding in digestion, removing wastes, lubricating joints, producing saliva, preventing infections, delivering nutrients to cells, maintaining optimal organ functions, regulating body temperature, and improving sleep quality, cognition, and mood.

Causes of dehydration  

Inflammatory bowel disease (IBD) like Crohn’s or colitis, Irritable Bowel Syndrome (IBS), Celiac disease, ischemia of the gut, colon cancer, and polyps can put you at greater risk for dehydration. In the case of IBD, IBS, and celiac disease, gut inflammation that results in the malabsorption of fluids, food nutrients, and electrolytes can lead to diarrhea and/or vomiting, causing fluid losses. Ischemia may be from a full or partially blocked blood vessel (possibly from an artery), or from low blood pressure that could reduce blood flow and damage intestinal tissues, thereby impairing fluid absorption. Treatments like radiation therapy for colon cancer may cause fever or GI distress like nausea, vomiting and diarrhea, subsequently resulting in fluid losses as well. The resection of parts of the intestine can also increase dehydration risk because such areas are the body’s primary sites for fluid absorption. With polyps, the fluid losses may be from a large overgrowth that blocks absorption, or it may be from fluid loss due to excess bleeding. Outside of the common GI issues, however, dehydration may also be largely from inadequate fluid intake. 

Signs of dehydration

Common signs of dehydration may include thirst, dry mouth/ lips/ gums/ nostrils, headaches, dizziness, fatigue, muscle cramps, confusion, lethargy, dark or cloudy urine, constipation, infrequent trips to urinate, reduced skin elasticity, flushed skin, low blood pressure, and increases in body temperature (i.e., heatstroke). In some severe cases of dehydration, there may be irritability, an absent or weak pulse, rapid heartbeat and breathing, and/ or loss of consciousness. If left untreated, dehydration can be life-threatening. Certain groups are more vulnerable to dehydration, such as babies, athletes, people with health conditions (diabetes or alcoholism), and older adults. 

If you are experiencing any of the above symptoms, visit a healthcare professional for assistance.


Mild to moderate dehydration can be treated by replenishing fluids. For mild dehydration, water is the best option, but there are other good options (i.e., chicken broth, coconut water, fruit juices, tomato juice, sports drinks, milk, soy milk, non-dairy fortified beverages). If you experience moderate dehydration through significant sweating, vomiting or diarrhea, you should choose an oral rehydration solution. If you are already at risk of dehydration due to your GI condition, sometimes, a mild dehydration can rapidly become moderate dehydration. If you experience vomiting, sucking on ice chips can help you to stay hydrated, but if vomiting persists,  you can take sips of an oral rehydration solution every 15 minutes for the first 3-4 hours. Severe dehydration may require hospital admission because you may need intravenous rehydration to replenish fluid and electrolytes. 

Oral Rehydration Solutions

Oral rehydration solutions (ORS) are highly effective in the treatment of mild to moderate dehydration because they contain the right balance of sodium, potassium, glucose, and fluids that are essential for recovery. The sodium and potassium help to maintain normal fluid balance and blood volume, while glucose helps with water absorption at the cellular level and encourages fluid retention. ORS are available in ready-to-drink liquids or powder that you dilute into water. Oral rehydration solutions can be found at pharmacies and retail stores. If you are unsure which ORS if right for you, ask your pharmacist. 


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