La Thalassotherapy(derived from the Greek word "Thalassa", meaning sea, and "Therapeia", or therapy), is a therapeutic treatment based on the use of marine resources (climate, sea water, seaweed, mud and other substances extracted from the sea) which is characterised by its use of totally natural elements. It has its origins in ancient Greece and the thermal baths of Roman times. One of the first references to the use of sea water as a therapeutic element was made by Hippocrates, while various papyrus' from Ancient Egypt also attest to the effectiveness of the muds of the Nile as a therapeutic element. But it was not until Roman times that thalassotherapy reached its peak, coinciding with the proliferation of thermal baths at the time.

Following a period of decadence which continued throughout the Middle Ages, interest in hydrotherapy was renewed from the 18th century onward and new techniques for the application of sea water were developed. Later on in the 19th century, thalassotherapy began to establish its presence in the tourism sector as a means of relaxation and improvement of the quality of life.

According to experts, marine surroundings and sea water itself contain more than 80 agents which are beneficial to the human organism, with wide-ranging properties including the treatment of tumours, viruses and bacterial infections. The composition of sea water is similar to blood plasma, and treatments using sea water favour the development of the natural process of osmotic absorption which occurs in all living cells and is based on the flow of water by way of diffusion from relatively pure zones with low concentrations of salts to zones of higher concentration through a semi-permeable membrane.

The end result is a balanced concentration between the two mediums. This process is enhanced by applying temperatures similar to body temperature (between 35 and 37º C), which facilitates the absorption through the skin of the elements contained in the water which contribute to its renovation, essentially iodine and sodium. Seaweed also has a beneficial effect, being a natural storehouse for a whole range of vitamins and with a high iron, calcium, protein and mineral content.