Diarrhea is a common condition in which a person passes loose, watery stool. In some cases, diarrhea may lead to dehydration, which can be life threatening.

Diarrhea may occur due to side effects from medications, infections, or underlying health conditions that affect the digestive tract.

A person should watch for signs of dehydration if they develop diarrhea. They should also take steps to maintain adequate hydration while they are experiencing diarrhea.

This article discusses signs of dehydration from diarrhea to look out for, potential complications, and steps to help prevent it.

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The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) defines diarrhea as loose, watery stool occurring three or more times a day. Acute (short-term) cases of diarrhea occur more commonly than chronic (long-term) or persistent diarrhea.

Diarrhea can lead to dehydration. People should seek medical attention if they think they may be experiencing dehydration. Though signs and symptoms of dehydration can vary, some of the most common include:

According to the World Health Organization (WHO), healthcare professionals can classify dehydration into levels based on symptom severity.

A person may have dehydration if they experience two or more of the following symptoms:

A person may have severe dehydration if they develop two or more of the following signs:

If a person does not display any of these signs, it is unlikely that they have dehydration. However, they should continue to drink fluids for the duration of their diarrhea. Drinking a steady amount of fluids, such as water or diluted fruit juice, should help maintain a safe hydration level.

Dehydration as a result of diarrhea can lead to severe complications and, in rare cases, death. Complications may relate to either the loss of fluid and electrolytes without enough rehydration or an overaggressive rehydration strategy.

Severe dehydration can lead to kidney damage, according to the National Kidney Foundation. This damage can occur due to a buildup of harmful substances in the kidneys that can lead to blockages. Some evidence suggests that even frequent periods of mild dehydration may result in permanent kidney damage.

Dehydration can also contribute to the development of urinary tract infections (UTIs) and kidney stones.

Other complications related to dehydration may include:

Complications associated with overaggressive rehydration can include peripheral edema, which refers to fluid collection and swelling in the legs or arms, and pulmonary edema, which refers to fluid retention and swelling in the lungs.

Learn about electrolyte imbalance.

The NIDDK notes that a person needs to replace both liquids and electrolytes when they have diarrhea to help prevent dehydration. Healthcare professionals refer to this as rehydration therapy.

Liquids that contain electrolytes include:

  • fruit juices
  • broths
  • sports drinks
  • caffeine-free soft drinks

Learn more about what electrolyte drinks are and how to make them.

It may help for people who are older or who have a compromised immune system to drink oral rehydration solutions, which help a person maintain the correct balance of fluid and electrolytes in their body. The solutions contain a combination of glucose, which is a type of sugar, and electrolytes.

Caregivers should encourage children with acute diarrhea to drink liquids containing electrolytes. While children can generally drink oral rehydration solutions, a person should speak with a healthcare professional for guidance before giving these solutions to a child.

If dehydration becomes severe, a doctor may administer IV fluids. This will introduce fluids and electrolytes directly into a person’s bloodstream.

A person can also take steps to help prevent diarrhea. Some prevention strategies include:

People should speak with a doctor if they think they may have an underlying condition that causes diarrhea.

Diarrhea is a common condition associated with loose, watery stools. It may lead to dehydration, particularly if a person does not replace lost fluids and electrolytes.

Dehydration can lead to potentially life threatening complications. A person should seek medical attention if they think they may be experiencing dehydration.

A person can take steps to help prevent dehydration as a result of diarrhea by drinking fluids that contain electrolytes, such as broths, juices, and oral rehydration solutions.