Top view of a bowl of Epsom salt
sasimoto/iStock/Getty Images

As popular home remedies go, Epsom salts have stood the test of time, having been first extracted from mineral springs near the town of Epsom, England, in the late 1600s. Epsom salts are a naturally occurring mineral called magnesium sulfate that is also easily manufactured. Epsom salts use as a laxative was apparently the first of its benefits to be recognized, being the subject of an essay called “A treatise on the nature and use of the bitter, purging salt” by Dr. Nehemiah Grew in 1697. If you are suffering from constipation and are considering using Epsom salts as a laxative, it’s important to know what you’re doing.

1. Consult a Doctor

If used properly, an Epsom salts solution is considered safe to drink for constipation for most healthy people, but the Epsom Salt Council recommends that you consult a health care provider before first use. People with kidney or heart problems should not drink an Epsom salts solution because of possible electrolyte imbalances and toxicity from magnesium or phosphorus. Even patients who are otherwise healthy may develop these complications as a result of excessive use. Older adults should be cautious using Epsom salts because of the potential for gastrointestinal side effects and magnesium toxicity.

2. Choose the Right Salt

In addition to Epsom salts for human use, there is an industrial version made for agriculture and other uses. It is unlikely that you’ll find anything in a pharmacy that’s not intended for human use, but make sure the package is marked “USP” (United States Pharmacopeia) and has a “drug facts” box that indicates it has met U.S. Food and Drug Administration standards.

3. Making the Solution

Most packages of USP-approved Epsom salts stipulate specific proportions of salt to water within a specific range. The salts dissolve more easily if the water is warm. Epsom salts have a distinctly bitter taste that some people may find offensive. This can be masked somewhat by adding lemon juice. When the solution is mixed, drink it as fast as you can.

4. Wait

Epsom salts are a potent laxative and the effects can be quite abrupt, so it’s a good idea to stay close to the bathroom until a bowel movement has occurred. Epsom salts usually work within 30 minutes to 6 hours. Epsom salts are what is known as an osmotic laxative, meaning they work by drawing water into the colon, creating water pressure that flushes out fecal matter. There is evidence to suggest that Epsom salts also work by stimulating the release of certain digestive hormones and neurotransmitters.