Premium Epsom Salt, magnesium sulfate, is known for its exceptional purity and therapeutic value. Available in medium grain, Premium Epsom Salt is ideal for use in a variety of applications, including home, spa, and garden. Epsom salt, named for a bitter saline spring at Epsom in Surrey, England, is not actually salt but a naturally occurring pure mineral compound of magnesium and sulfate. Long known as a natural remedy for a number of ailments, Epsom salt has numerous beneficial health, beauty and even household and gardening-related uses.