According to Charaka. Ayurveda is the science of longevity. Rasayana Chikitsa (Rejuvenation therapy) and Vajeekantna Chikitsa (Virilization therapy) constitute two parts of the ashtanga (eight parts) of Ayurveda. According to the ayurvedic pharmacopoeia, any aged person who undergoes a six-month course of rejuvenation and virilization can he transformed into a healthy youth.

The person most suited to undergo this transformation, says Charaka, is "one who has discarded all sins from the heart and strengthened himself with resolution. is full of faith and wishes the welfare of ail beings." First the body has to be cleansed of all toxins by undergoing the purifying procedures of Panchakarma. After this, the person enters into the kucli, the special hut. where he/she will undergo treatment under the supervision of an eminent physician.

Vivid descriptions can be found in classical texts of how and where the hut is to be built. The place should abound in medicinal herbs and should be inhabited by princes, physicians and Brahmins. The hut should face the east or south and be designed to allow the entry of fresh air while excluding direct sunlight and wind.
There has not been any authentic recording of  therapy in this century.