Abstract
Ayurveda refers that every Dravya is constituted by five elements i.e. Prithvi (earth), Ap (water), Agni (fire), Vayu (air) and
Akasha (ether). General principles of Drug action are enumerated as Rasapanchaka i.e. Rasa (taste), Guna (quality), Virya
(potency), Vipaka (metabolism) and Prabhava (specific principle). Among them the first four principles are categorized under
rational principles while Prabhava is designated as empirical component as its activity is inexplicable. CharakaSamhita (1000
BC) has furnished the assessment of these principles in brief ‘Rasa of Dravya (food/drug) is known by direct perception;Vipaka
can only be inferred from its action. As regardsVirya it may sometimes be inferred from its actions on the body and also be
known by direct perception’Rasa is identified at tongue level and it depends on individual’s perception. Rasa serves as a tool to
infer the Panchabhautika composition of the Dravya and facilitates for identification of spectrum of activity of a particular
drug. Acharyas of Ayurveda furnished certain characteristics of individual Rasas along with their actions on the body. Since this
principle’s identification depends solely on the individual’s ability to perceive it, a structured proforma is developed to assess
the Rasa of non-classical drugs from Ayurvedic perspectives in healthy volunteers.

Key words: Assessment of rasa, Non-classical drugs