It’s a complete science of herbal plants, in other terms Materia Medica.

It’s including pharmacognosy, pharmacology and therapeutic uses of the plants. Ayurvedic drugs, especially herbs are prescribed in different pharmaceutical forms, to get maximum therapeutic effect.

The word dravyaguna consist of 2 words:
1) Dravya = material of thing which can be living or not living.
2) Guna = properties According to Charaka their is nothing on the earth which is not medicine.

That’s why Ayurveda considers all substances as medicine, if used for specific purposes in an appropriate way.