Q: What are Epsom salts made of, and why are they called that?
Epsom salts is the common name for magnesium sulfate, a magnesium salt sometimes abbreviated as MgSO4. According to the the United States Dispensatory, in 1675 Dr. Grew documented how he obtained magnesium sulfate crystals from evaporating the mineral water of Epsom, England. Because the mineral water from the Seiditz Spring in Germany was nearly identical to the water from Epsom, both Seiditz salts and Epsom salts were used interchangably to refer to magnesium sulfate, but over time the name only the name Epsom Salts stuck.
By the late 1880s a new process was developed for producing both table salt and Epsom salt. Instead of having to mine it, salt could be produced by evaporating water from the sea. After extracting the desirable sodium chloride from seawater the brine left over contained nearly pure magnesium sulfate. Although in Colonial America magnesium sulfate was produced from veins of rock near Baltimore and in southern Pennsylvania, today’s Epsom salts are still produced by evaporating seawater.
Magnesium sulfate is widely used today both externally as either a poultice or solution for soaking, and internally as a cathartic. Often packaged in quart sized milk cartons, Epsom Salts is a white, odorless powder that tastes salty and bitter. Cathartics like magnesium sulfate relieve constipation by helping fecal matter move through the colon and rectum. Many cathartics are derived from natural sources, and have been often added to patent medicines in America.
Cathartics are classified in two different ways: by how they work and the intensity of their effect on your bowels. There are 4 groups of cathartics named for how they work, including irritants or stimulant laxatives, bulk or saline laxatives, emollients and fecal softeners. The older system of grouping by intensity has 3 categories: “laxatives”, “purgatives”, and (gulp) “drastics”. Epsom salts are classified as a saline laxative and depending on the concentration used are considered either a laxative or a purgative.
Other magnesium products that share a stimulant action on your bowels include magnesium hydroxide and magnesium citrate. Magnesium hydroxide is less powerful than the sulfate version, and has a milky white color, giving it the name milk of magnesia. Some liquid antacids contain magnesium hydroxide, including Maalox® and Mylanta®. Magnesium citrate, a clear solution of magnesium contains extra sodium bicarbonate and citric acid to make it effervescent. It is still available in a glass bottle as citrate of magnesia.
How does Epsom salts work? When you add the crystals to water, the result is concentrated, salty water. If you drink it, it will “pull” water out of your body and into your intestines, making your stool more liquid. The increased watery bulk of your stool encourages it to move more quickly through your intestine, colon and rectum. The more concentrated the solution of magnesium sulfate, the more powerful its effect as a laxative.
Soaking in the concentrated salty solution of Epsom salts dissolved in warm water works to shrink tissues surrounding an injury. The ability of magnesium sulfate solution to pull fluid out of tissues can be helpful in decreasing swelling and pain. Soaking in warm Epsom salts softens and shrinks the skin making foreign bodies like splinters and insect stingers easier to remove. Some people add Epsom salts to bath water for soaking in or as a therapeutic bath to relieve muscle and joint aches.
The Epsom Salt Council was formed in 1993 to encourage the use of their product. They have a website promoting Epsom salts at www.epsomsaltcouncil.org, with sections suggesting uses in the garden, as a beauty aid, in crafts and for health.
Epsom salts are safe when used externally for soaking, but be careful about using it by mouth, as the amount of magnesium that is absorbed into your body can be unpredictable. One woman died from gargling with Epsom salts due to absorbing excessive magnesium, causing her heart to stop. Another woman almost died from heart block after using an enema made from 3 tablespoons of Epsom salts dissolved in warm water. Two children went into cardiac arrest and one of them died after consuming several doses of a mega-mineral supplement containing magnesium. If you use Milk of Magnesia or magnesium citrate for constipation, please DO NOT exceed the doses recommeded on the label.
