Dravyas

Dravyas are the 'things' which has got functions and properties. All dravyas are perceived by mind through one or more 'indriyas'(senses). It contains the properties of 'mahabhoothas'(sound, touch, form, taste and, smell). Due to the peculiarities of the combination of 'mahabhoothas', stable dravya itself will show marked differences in characteristics. Hence, dravyas are classified as 'prudhiva', 'aapya', 'aagneya', 'vaayavya', and, 'aakasya'. Since Ayurveda studies about dravya with an aim of the use and application of dravya as food and medicine, the knowledge about the properties like taste, etc., is enough to determine the utility of dravya. The utility of dravya depends on the 'rasa', 'guna', 'veerya', 'vipaka', and 'prabhava'. Of these properties, taste (rasa) plays an important role in Ayurveda because dravya is taken as food or medicine.

RASA - There are six rasas madhura (sweet), amla (acidic), lavana (salty), thikta (pungent), katu, and kashaya. Dravyas taken as food or medicine can correct the imbalance of doshas. This is due to to the gunas. The gunas of food or medicine increases the dosha which has the same guna. It was found that madhura, amla, and lavana rasa decrease vatha while all other rasas increase it. Similarly, thikta, katu, and kashaya rasa decrease kapha while all other rasas increase kapha. Kashaya, thikta, madhura rasas decrease pitha while the other rasas increase it. Rasas in dravya are present by virtue of the 'panchabhootas'contained in the dravya. The six rasas are formed as follows.

• Madhura - due to the increased presence of 'pruthvi' and 'jala'
• Amla - due to the increased presence of 'agni'
• Lavana - due to the increased presence of 'jala' & 'agni'
• Thikta - due to the increased presence of 'akasa' & 'vayu'
• Katu - due to the increased presence of 'agni' & 'vayu'
• Kashaya -due to the increased presence of 'pruthvi' &'vayu'

GUNA -Another property which is inherent is called guna. There are twenty gunas as given below.

• guru (heavy) - laghu (light)
• mandam (slow) - theekshanam (fast)
• seetham (cold)- ushanam (hot)
• snigdha (oily)- rooksha (rough)
• sleshmam - gharam
• sandram - dravam
• sookshmam (micro)- sthoolam (macro)
• visadam - pichilam
• sthiram (static)- chalam (mobile)
• mrudu (soft)- katinam (hard)

VEERYAM -Dravyas has veeryam, the potency to manifest work. It is classified into two namely Ushnaveeryam and Seethaveeryam. Actually these two are gunas which present in abundant and hence behave differently. VIPAKA - A rasa of dravyam after it has undergone digestion get transformed into three rasas called 'vipaka' of that rasa. Madhura and lavana becomes madhura, amla becomes amla itself, and katu and kashaya becomes katu after digestion by Jataragni. Knowledge of vipaka is needed in understanding physiological changes.

PRABHAVA - is the power of dravyam to manifest work in its unique way. When rasa, guna, veerya, and vipaka in a substance is found same as in another substance, but in action the two substances differ it is said that the change is due to 'prabhava' of dravyam. For example, 'danthi' is having the same rasa, vipaka, veerya and guna of 'chithraka'. But 'danthi' produces 'virechana' while 'chithraka' don't. So the action of 'virechana' found in 'danthi' is due to its prabhava.