Prabhava stands at the opposite end of Virya. Whereas Virya is explainable on the basis of Bhautic composition, Prabhava is something that cannot be explained.
When the drug though having similar Rasa, produce different effect, it is said to have Acintya Sakti or Prabhava. This energy cannot be explained on the basis of theory. Ayurveda attempts to explain all such actions individually. To meet that end, Ayurveda is committed and extensive research work is going on, till this date.
AYUCARE AND HASF 
Prabhava 
