The first subjective experience of a substance on the tongue is taste (rasa). A short time later, one feels heating or cooling energy (virya). Finally the substances have an action on urine, faeces and sweat (vipak). For instance, for hot chilli peppers, one immediately experiences its pungent taste and heating energy; observing a burning sensation in the faces and urine the next day.
Virya – Heating or Cooling Energy
When any medicinal herb or food substance is put in the mouth, the first experience is its taste. Later, and in some cases immediately, you feel its heating or cooling energy, either in the mouth or stomach. This change is all due to its action or potent energy called Virya.
By experience, one can form general rules about what a taste “feels like” in the body. For example, the sweet taste has a cooling energy, due to its heaviness. This action provokes kapha and is pleasing to pitta and vata. But there are occasional exceptions to this rule. Honey and molasses are sweet but have heating energy. This unexpected effect is termed Prabhav. In this same way, sour taste is usually heating expect in the instance of lime, which is cooling.
Vipak – Post-Digestive Effect
The final post-digestive effect of the taste on the body, mind and consciousness is called Vipak. While sweet and salty taste have a sweet vipak, sour taste has a sour vipak, but that of pungent, bitter and astringent tastes are all pungent. Knowledge of the energy and post-digestive effect of food or medicinal herbs makes understanding of its action on bodily system easy. This knowledge being essential for both healing and cooking.
Prabhav – Specific Unexplained Action
When two substances of similar taste, energy and post-digestive effect show entirely different action, it is called prabhav. There is no logical explanation for this. Ghee (clarified butter) in doses of two teaspoon with a cup of milk is laxative but in smaller dose, like half a teaspoon, is constipating. Why? The answer is prabhav. All gem stones, crystals and mantras aid healing due to their prabhav.
Prabhav is therefore the specific, dynamic, hidden action of the awareness present in the substance.