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Is salt water flush harmful?

Salt water flushing, also known as a salt water cleanse, is a method some people use to quickly clean out the bowel before a colonoscopy or to detox and lose weight quickly. It involves drinking a salt water mixture to rapidly flush the colon. But is this practice safe and effective? There are some risks and downsides to be aware of.

What is a salt water flush?

A salt water flush involves drinking a saline solution on an empty stomach to produce watery bowel movements and clear out the colon. The basic recipe is:

  • 2 teaspoons of non-iodized salt
  • 1 quart of warm water

The salt draws water into the colon to induce contractions and flush out the contents. Some people drink additional fluids like water or herbal teas after the solution to push out more stool.

Many people use a salt water flush to prep for a colonoscopy so the doctor can see the colon walls clearly. Others use it before fasting or cleansing programs to start with an empty colon. Some simply use it occasionally to alleviate constipation.

Proponents believe salt water flushing removes waste from the colon to prevent toxins being reabsorbed and improve digestion and energy levels. However, there are some risks to be aware of.

Potential dangers of salt water flushing

While using salt water as an occasional laxative may not be harmful for most people, regularly flushing with salt water has potential risks including:

  • Dehydration – The large water loss from diarrhea can lead to dehydration, particularly if you don’t drink enough fluids afterward.
  • Electrolyte imbalances – The rapid mineral loss may disrupt levels of electrolytes like sodium, potassium, and magnesium.
  • Severe diarrhea – Drinking too much salt water can cause profuse, watery diarrhea leading to dehydration and mineral depletion.

Salt water flushing is not recommended for children, pregnant women, older adults, people with kidney disease, heart problems, or other major health conditions. It may also interact with some medications.

Limited research on effectiveness and safety

Despite the popularity of salt water flushing, there is very limited scientific research on its safety and efficacy. Potential issues include:

  • It likely does not remove all waste and toxins – while it empties the colon, a flush won’t have significant effects on waste stored elsewhere in the body.
  • May disrupt gut bacteria – the resulting diarrhea can wash out beneficial bacteria needed for immunity and digestion.
  • Can be habit-forming – using it too often can lead to dependency, aggravating constipation when not used.

There are no rigorous studies on the long-term safety of regularly flushing with salt water. Potential risks like electrolyte disturbances have not been well-researched.

Healthier alternatives for constipation relief

Instead of routinely flushing with salt water, try safer ways to keep bowel movements regular like:

  • Eating more fiber – aim for 25-30g daily from fruits, vegetables, whole grains, nuts and seeds.
  • Drinking more fluids – water, herbal teas, fruit/veg juices can aid digestion.
  • Exercising regularly – aims for 150 minutes per week to stimulate the gut.
  • Establishing toilet routines – go when feel urge and allow enough time to relax.
  • Managing stress – relax with yoga, meditation, massage, as stress inhibits bowel function.

If constipation persists, consider natural laxatives like psyllium husk, flaxseed, prunes or probiotic supplements. See a doctor to address ongoing issues.

Is salt water cleansing acceptable before a colonoscopy?

Drinking a salt water solution is commonly recommended before a colonoscopy to empty the bowels and get clear views. This procedure is generally considered safe for otherwise healthy adults for occasional use before medical procedures. However, there are some caveats:

  • Ask your doctor about the prep timing and fluid amounts – drink as instructed.
  • Stay near a toilet once you start – urgent diarrhea occurs within hours.
  • Drink adequate fluids after to replace losses.
  • Inform your doctor of any problematic symptoms like vomiting, weakness.
  • Do not drive until the effects have worn off.

The strong laxative effect helps visualize the colon properly during the exam. But remember it is for short-term use and not advised for regular colon cleansing.

Typical salt water cleanse protocol

If undertaking a salt water flush, here is typical protocol to follow:

  • Avoid solid foods for 12-24 hours beforehand.
  • Prepare the solution – 2 teaspoons salt in 1 quart warm water. Can flavor with lemon.
  • Drink on an empty stomach first thing in the morning.
  • Aim to retain for 5-15 minutes before bowel movements start.
  • Stay near a toilet for rapid effects.
  • Drink plenty of water, coconut water or herbal tea afterward.
  • Rest and take it easy – avoid strenuous activities due to diarrhea.

Never do a salt water cleanse for more than 24 hours. Seek medical help if you experience concerning symptoms like dizziness, muscle cramps or rapid heartbeat.

Who should not attempt salt water flushing?

Salt water cleansing is not suitable for everyone. You should not attempt it if you have:

  • Heart failure, hypertension or low blood pressure
  • Chronic kidney disease
  • Liver cirrhosis
  • Eating disorders
  • Ulcerative colitis, Crohn’s disease or bowel obstruction
  • Are pregnant or breastfeeding
  • Are a child or adolescent

It also may not be advisable if you take diuretics, lithium, corticosteroids or medications that influence electrolyte levels. Talk to your doctor.

The risks versus benefits of salt water flushing

To summarize, here are the main pros and cons of using salt water cleansing:

Potential Benefits Potential Risks
  • Empties colon before colonoscopy
  • May provide short-term relief of constipation
  • Can cause severe diarrhea and dehydration
  • May lead to electrolyte imbalances
  • Disrupts gut microbiome
  • Not a long-term solution for constipation

When weighing up the evidence, the potential risks seem to outweigh the benefits for most people. More research is still needed on the safety and efficacy of routinely using salt water cleansing.


While salt water flushing may seem like a quick fix for constipation or removing waste from the body, it comes with substantial risks. The resulting diarrhea can lead to dehydration and electrolyte disturbances, and it may disrupt the gut microbiome. There are also limited studies on the long-term safety of regular use.

For occasional use before a colonoscopy, salt water prep may be acceptable if done carefully under medical supervision. But there are healthier ways to manage constipation long-term, like eating more fiber, exercising and managing stress.

Unless recommended by your doctor, salt water cleansing is generally not advisable due to the risks. More research is still needed to determine if it has a role as a safe, effective cleansing technique.