Magnesium sulfate is used in bath salts, particularly in flotation therapy, where high concentrations raise the bath water's specific gravity, effectively making the body more buoyant. Traditionally, it is also used to prepare foot baths, intended to soothe sore feet. The reason for the inclusion of the salt is partially cosmetic: the increase in ionic strength prevents some of the temporary skin wrinkling (partial maceration) which is caused by prolonged immersion of extremities in pure water. Magnesium and sulfate ions are naturally present in some mineral waters. The claimed health benefits of Epsom Salt baths have not been proven.