Tantric practitioners experimented with achieving physicl immortality. The by-products of these experiments were adopted into ayurvecia as medicines. Kaflali, the black sulphide of mercury which is the basis of a wide variety of Ayurvedic medicines! mentioned in the 7th century treatise Ashfanga Hrdaya by Vagabhata. By the time Sharngadhara wrote his Sharngadhara Samhita in the 13th century, mineral medicines had becam popular in northern India.

There are many possible reasons why minerals plants in northern India, and to some extent in western India as well. Incinerated minerals make good because, by and large, they get better with age and no expiry date and no danger of waste. There is no yearly expeditions to collect and preserve herbs, sind can be handed down from generation to generation, are less cumbersome to administer. They are also powerful than all but the most potent (or poisonous) of herbs, and so small doses produce large effects faster than herbal products can.

A more esoteric reason involves astrology: each of the planets Has a metal and gem associated with it (for example, silver and Pearls for the moon, and iron and blue sapphire for Saturn), the ingesson of which helps to reduce that planet's negative effects on the individual.

Another explanation comes from historical politics. The Muslims who conquered parts of north India brought with them their own medical sustem with its strong alchemical tradition. Southern India. especially Kerala, being little influenced by the muslims, preferred to continue with vegetable drugs.

The breakdown of Brahmanism as a political force in northern India, and its gradual supplanting by devotional cults and Tantra explains the rise of simplified folk medl-cines and the development of Tantric medicine.