There has been a shift in universal trend from synthetic to herbal medicine recently. It is ancient wisdom that plants have therapeutic
value and are used to treat various diseases since Neanderthal age. All ancient civilizations in the world are known to use plants for
medicinal purposes. Ayurveda and traditional medicines are well known to the world for their natural ingredients and multiple
benefits. Medicinal Plants play an important role in human life to combat diseases since time immemorial. Bronchial Asthma is a one
of common respiratory disease in Sri Lanka that affects the all age groups. In Traditional Medicine in Sri Lanka Bronchial Asthma is
correlated with Shw?sa R?ga and suggests number of decoction formulas (Kash?ya Vatt?ru) for this disease. The purpose of this study
was to determine a pharmacodynamic action of selected decoction formulas for Shw?sa R?ga and recognize the action of these
decoction formulas towards on Pr?navaha Sr?tas. This study was done by using traditional medicine text books. After referring these
books, thirty decoctions were selected for Shw?sa R?ga. Out of those, ten decoction formulas were randomly selected and
Pharmacodynamic action was elicited and the effect of Pr?navaha Sr?tas was analyzed in that ten decoction formulas. After analyzing
of all Rasa of each and every formulas; Katu, Thiktha and Kash?ya are obvious and the percentages of those are 27.53%, 27.53%, and
20.22% respectively. The percentages of Lagu, R?ksha and T?kshna guna are 24.85%, 20.00%, 10.30% respectively. And also
Kaphagna action is 67.79% and Kapha Niss?raka action is 32.89%.The conclusions were Katu, Tiktharasa, Lagu and Guru guna,
Ushna veerya and Katu vip?ka ingredients are frequently used in decoction formulas for Shw?sa R?ga in Traditional Medicine in Sri
Lanka and also the used ingredients in decoction formulas either act on Kaphagna or Kapha niss?raka on Pr?navaha Sr?tas.