Ayurveda has two main goals - one is to stay healthy and the second is to cure the disease. The branch of rasayana or rejuvenation is one of eight specialized parts of Ayurveda, which primarily concerned with the preservation of health. Rasayana is defined as a spice, food, or any activity that provides youthfulness. If taken in the right way, the rasayana prevents premature aging and keeps you young and active both physically and mentally.
The literal meaning of rasayana is "increasing rasa, the vital fluid produced by the digestion of food. Rasa provides nutrition, enhances immunity and maintains life. Rasayana is the treatment method by which the rasa is maintained in the body. The purpose of rasayana is for strength, immunity, Ojas, vitality, willpower and determination, and to strengthen the sense faculties, so you are not exposed to diseases and conditions, as long as you live.