Ayurvedic pharmacology is termed Dravya vignan – ‘the science of drugs’. The Dravya or drug is Panchabhautik or composed of Panchabhutas / five elements. Ayurvedic pharmacology is based on the concept of these five great elements. 

There are five categories of Dravya, each based on the inherent element of Panchabhuta that predominates : Parthiva (earth), Apya (water), Taijasa (Fire), Vayavya (Air) and Nabhasa (Ether). They are further classified into three according to the source from which they are derived. They are Jangama, Bhauma, Audbidha.