Thalassotherapy is a spa treatment based on algae. Algae concentrate all the properties of the sea and for that reason up until nowadays a lot has been said about their importance as a therapeutic instrument to tackle the various health disorders and aesthetic problems. The action of algae is based on the phenomenon of osmosis created between the body and salt water. Scientific studies have presented similarity between the metal composition of seawater and the composition of fluids in the human body (lymph, blood plasma).