Rasayana is a special type of treatment containing various methods of rejuvenation. It derives from 'Rasa' and 'Ayana.' The literal meaning of Rasa is the essence of something. Anything ingested into the body in the form of food or medicine is first resynthesized into Rasa Dhatu, the basic plasma tissue. Ayana is the method by which Rasa is carried to all the body tissues for biochemical metamorphosis (Rasakriya). The concept of Rasayana is based on these two principles of conservation and transmutation of energy. Rasayana therapy strives to improve physical, mental and moral Qualities. It prevents old age, restores youthfulness, improves the complexion and the voice, and increases physical strength and immunity. It strengthens memory and intelligence, gives happiness to oneself, and a life which is beneficial to others.