The earliest recordings of salt baths date back to 2700 B.C. when they appeared in the earliest pharmacology publication in China. Hippocrates also encouraged his healers to take advantage of the healing properties of salt by telling them to immerse their patients in salt water. This treatment continued in ancient Greece and in ancient Rome. In Egypt the benefits of salt on the skin were also exploited through cosmetic treatments as Cleopatra herself would soak in the salt and mineral rich waters of the Dead Sea. In Rome, salt was so valued that the Roman soldiers were actually partially paid in salt, hence the word "salary".
Later, in 1753, English author and physician Dr. Charles Russel published "The Uses of Sea Water". It also has been historically known that going to the ocean for its sea water or going to bath houses or sanitariums with salt baths has always been beneficial in treating many ailments.
In the present day, many spas use salt for a myriad of skin treatments and cosmetic applications including salt baths and foot soaks.