Drugs act by certain qualities in them. Qualities and actions have no existence without substance. While substance is capable of existing independently by itself, quality cannot exist; it abides in substance and has itself no qualities.

In Ayurveda, the dietetic and medicinal substances are considered to be essentially composed of the five proto-elements.  These elements have some primary qualities in them, viz, Akasha has laghu quality, Vayu has ruksha quality, Tejas has ushna or teekshna quality, apa has snigdha quality and prithivi has guru quality. Substances having tejas as one of the predominant constituents are Ushna in quality and the rest are sheeta. The predominant proto-elements in a substance subscribe their qualities to it. Besides, the specific arrangement and preponderance of the specific proto-elements in substances give rise to the secondary qualities as Rasas, which are perceived with the tongue. Obviously, the combination and preponderance of the particular two proto-elements give rise to one particular taste and that taste (Rasa) inherits the qualities of those proto-elements. This is why, for instance, Madhura rasa, predominantly composed of Prithivi and Apa proto-elements. Have three qualities like snigdha, sheeta and guru. Similar is the case with all the rasas. Obviously, when we say about the qualities of rasas, are mean the qualities of the substance having that Rasa. The Rasa is in other words, the chemical structure of substance having some qualities. When the substance is ingested, it first comes in contact with the tongue and shows some local and indirect actions. These actions are explained on the basis of rasas and their qualities (gunas). Substances undergo certain chemical changes during digestion and metabolism. This is what is called Vipaka, which is ascertained from the actions it produces in the body. These actions are seen on the Doshas, dhatus, malas and Srotamsi the potent qualities survived during digestive and metabolic changes are, then called Virya, instead of guna.

As substances are digested and rendered assimilable, only useful portion is assimilated and qualities of the surplus or useless portion of substance are, therefore, dropped. Only the qualities of the assimilated portion of substances show their actions in the body. These potent pharmacotherapeutic qualities are termed as Virya.

The potency of drug by which it performs its actions right from its ingestion till excretion, with special reference to its action on the dosha-dushya Sammurehhana, is called Virya.

The main aim of the drug therapy is to mitigate or cure the disease, which result from the imbalance of the Doshas, dhatus and Malas in the body. This imbalance is understood in terms of increase (Vriddhi) or decrease (Kshaya) of the body-elements. The treatment is also of two types, viz Santarpana and Apatarpana. Santarpana treatment is employed for increasing the decreased body elements to normal. The apatarpana treatment is employed for decreasing the increased body-elements to normal level. These two types of actions are represented by two types of Viryas,viz

  • Sheeta Virya representing Santarpana treatment.
  • UshnaVirya representing Apatapnana treatment.


      Ushna Virya

        Sheeta Virya

Effect on Doshas

Pitta Increase

Decrease Vata and Kapha

Increase Vata and Kapha

Decrease Pitta







Blood pressure



Basic metabolic Rate




Hard or difficult