To reduce the toxicity (''vikasi guna'') of ''Danti'' and ''Dravanti'', Charaka evolved a process using ''Pippali'' and honey paste which is to be besmeared over the roots and once again to be smeared with mud and fomented with steam after drying up in sun. Chakrapani observes that heat of fire and sunrays makes the root free from adverse effects. This could be quoted as a best example of purification process employed for the removal of toxicity - a novel concept mentioned by Charaka. In the medieval ages, ''Rasashastra'' texts adopted several purificatory procedures for various herbal and metallic drugs.
=== Relevance of the concepts of [[Kalpa Sthana]] in the current clinical practices ===