White bath salt in a wooden bowl
Bborriss/iStock/Getty Images

Named after the town of Epsom in England, Epsom salt is a widely used health and beauty product. Derived from distilled mineral-rich water, this magnesium sulfate compound is well known as a traditional home remedy for treating constipation and colon cleansing -- despite sparse research on its effectiveness. Although Epsom salt can be safely used as a laxative, large doses can pose significant health risks. It’s important to discuss intended use with a physician, especially if you have any ongoing health problems or if you are pregnant or breastfeeding.

Colon Cleansing

There are several methods used to cleanse the colon or rid the intestines of fecal matter. Consuming more dietary fiber or using fiber supplements adds bulk to the stool, while certain foods and medications soften the stool or stimulate intestinal muscles to move more, which helps empty the colon. Epsom salt works as an osmotic laxative which draws more fluid into the gut. According to a review published in the December 2009 issue of “Neurogastroenterology and Motility,” osmotic laxatives and magnesium-containing laxatives can be effective in increasing stool frequency, however this review noted that no specific trials have been completed on the use of Epsom salt.

Mechanism of Action

Osmotic laxatives such as Epsom salt stimulate the intestine to absorb excess water from the body. As this magnesium sulfate compound enters the intestines, fluid is naturally pulled into the gut -- softening the stool, increasing stool volume and causing more frequent bowel movements or even diarrhea as the bowel empties. Although clearing fecal matter out of the intestines is essential prior to certain surgeries and diagnostic tests, it’s also common for people to try colon cleansing to promote health, lose weight or rid the body of toxins. However, evidence to support these claims is limited, according to a August 2011 article in “The Journal of Family Practice.”

Epsom Salt Use

Although Epsom salt has been used for generations, there is a lack of evidence-based recommendations on the use of Epsom salt for colon cleansing. Package directions for treating constipation suggest a dose of 2 to 6 teaspoons of Epsom salt. The salt must be mixed with at least 8 ounces of water or fluids to avoid dehydration. Since the Epsom salt solution can cause the colon to empty completely, anyone using this method would benefit from starting the process in the morning and staying near a bathroom.


While Epsom salt has been FDA approved for use as a laxative, it has not been approved specifically for colon cleaning. There is a potential for side effects and serious safety risks with large or frequent doses, or if used by people with health problems such as kidney disease. When excess fluid is pulled into the intestines, bloating, gas, abdominal discomfort and diarrhea can result. If diarrhea is excessive, dehydration can also occur. Finally, some of the magnesium sulfate from Epsom salt is absorbed in the intestines. Although the kidneys function to rid the body of excess magnesium, there have been case reports of magnesium toxicity with Epsom salt use, according to an April 2009 article published in “BMJ Case Reports.” This risk of excess body magnesium -- a life threatening condition -- is more likely in people who have kidney disease.

Warnings and Precautions

Always consult your doctor before using an Epsom salt laxative. This is particularly important if have an existing medical condition or if you take any prescription medications. Do not use if you have kidney disease, high magnesium levels or if you are pregnant or nursing. Avoid use in children unless prescribed by a doctor. If your doctor approves the use of Epsom salt as a laxative, follow dosing directions. Also, do not use more than once daily, and do not use for more than 1 week unless you have discussed longer-term use with your doctor. If you have ongoing constipation, or a change in bowel habits that last more than 2 weeks, this can indicate a more serious health problem, so see your doctor for evaluation and treatment recommendations.

Reviewed by: Kay Peck, MPH, RD