According to Siddha medical science, the Universe originally consisted of atoms which contributed to the five basic elements, viz., earth, water, fire, air and sky which correspond to the five senses of the human body and they were the fundamentals of all the corporeal things in the world. A close relationship is found to exist between the external world and the internal system of man. Man consumes water and food, breathes the air and thus maintains the heat in the body. He is alive on account of the life force given by ether. The earth is the first element which gives fine shape to the body including bones, tissues, muscles, skin, hair etc.
Water is the second element representing blood, secretions of the glands, vital fluid etc.
Fire is the third element that gives motion, vigor and vitality to the body. It also helps digestion, circulation and simulation besides respiration and the nervous system. Above all, ether is the characteristic of man's mental and spiritual faculties. Siddha system of medicine is based on Saiva Siddhantha. The faculty of reducing gross body to the size of an atom and to enable him to fly in space.