The mineral springs at Epsom, England (in Surrey) were renowned for their curative properties since ancient times. Enterprising souls boiled the water and sold the salty residue which remained as a healthful nostrum (likely spelled "Ye Saltes of Eppsomme"). Unlike almost all of the elixirs, tonics, and other folk remedies or yesteryear, this stuff actually worked.
Epsom salts (or salt, the terminal -s is customary, but is frequently left off nowadays) are magnesium sulfate, MgSO4, typically in its heptahydrate form (MgSO4ยท7H2O). This compound is prescribed as a magnesium supplement and used by physicians for control of cardiac arrhythmia, eclampsia, treatment of tetanus and migraines, and as a bronchodialator and tocolytic agent. Obviously, this is a very versatile compound, but the usefulness of Epsom salts does not stop there by any means.
Around the home, Epsom salts are typically used in a bath—add two cups of salts to a regular-sized bathtub (more for larger tubs). A hot bath with Epsom salts can ease muscular pain, soften skin, reduce swelling and bruising, and detoxify the body. It will also open the pores and help to cleanse the body, making the skin softer and more supple in the process. This is especially useful for tired, overworked muscles and tissues and may be helpful in relieving such conditions as athlete's foot, rashes, and other minor skin irritations and infections. For an invigorating treat, a few drops of eucalyptus oil may be added to the bath.
Both components of Epsom salts, magnesium and sulfate, can be absorbed into the body simply by soaking in a bath. Magnesium is a very important electrolyte necessary for the proper functioning of muscles, nerves, and certain enzymes, it is probably best-known for its prevention of cramps and easing of muscular pains. Another of the potential benefits of increasing magnesium levels is improved nervous system functioning, this may enhance mental focus and clarity, as well as quality of sleep. Magnesium levels are implicated in the regulation of mood swings and there is evidence that it may aid in controlling blood pressure as well.
Sulfate assists in the absorption of nutrients, and in repair and building of joints and tissues in the nervous system. Increasing the serum sulfate ion concentration may also aid in the flushing of toxins from the body and reduce the severity of migraine headaches.
Apart from their bath-time uses, Epsom salts may also be added to cleansing cream to make a very effective facial scrub. Similarly, massaging a handful of Epsom salts over wet skin will cleanse, exfoliate, and soften rough spots. A warm compress soaked with Epsom salts reduces swelling and soothes the itch and discomfort of insect bites and stings.
Epsom salts may also be used in the garden, sprinkled around plants for improved chlorophyll production and uptake of nutrients. Gardeners usually use Epsom salts for flowering plants (especially roses), evergreens, shrubs, and tomatoes. The Epsom Salt Council has a wonderful web page detailing some of the horticultural uses of this product (www.epsomsaltcouncil.org).
The healthful springs at Epsom are no longer used to make this salt—it is more commonly refined from the mineral epsomite (mined or produced artificially), and it is abundant and inexpensive. In one recent shopping expedition, I found a four pound (not quite 2 kg) bag for about two dollars and a six pound bag (about two and a half kg) for four dollars. This versatile salt is a clear winner when it comes to body care!
References:
This article was originally commissioned by a colleague of mine and I gave it a new coat of paint for E2
Wikipedia
epsomsaltcouncil.org
Taber's Cyclopedic Medical Dictionary, 19th edition (FA Davis, Philadelphia, 1997).
Beers, Mark H., editor in chief, "the Merck Manual of Medical Information" second home edition (Merck Research Laboratories, Whitehouse Station, New Jersey, 2003)