It is very popular in Ayurveda culture or in the field of Ayurveda i.e. Ayurveda is Shasvata (immortal). The real meaning of being Shasvata is endless that which never dies. We can understand this concept of endlessness with the story of “shiva” origin. 

It is one of the story which is about the origin of Shiva, in Shiva Purana (collection of many compendium over shiva). In that once both Brahma & Vishnu heard a continuous sound of Omkar in the cosmos. They reached near the sound which is in the form of a stream. They asked about its origin and start searching about the same, at the end they both got disappointed for not finding its origin. So that shows the endless form of Shiva (something which has no any starting or end point). At that time Shiva told himself superior to other two Gods (Brahma and Vishnu) and he also mentioned himself as the origin without any shape or shapeless. The time of origin is celebrated as the shivaratri in the whole World especially in India.  In the same context there is a word called as “Shasvata” which is very profoundly used for Ayurveda that fully means that it never ends.

Whatever be the situation or condition it will never destroyed by any means. It can be altered in many ways but never comes to an end. This is because if someone really ask about the origin source of Ayurveda then the answer is that it comes from the mouth of lords Brahma (the creator of mankind as per Hindusim). So it is never been a science which is learned or experimented. It directly comes from the mouth of the God itself.