Epsom Salts (magnesium sulphate) derive their name from a salty spring in Epsom, Surrey. Power Health Epsom Salts are suitable to take as a food supplement and for external use - as bath salts. When used in the bath, Epsom Salts may be helpful in relieving joint and muscle aches and acting as a skin softener. Taken internally, Epsom Salts can be used as a laxative.