For over 400 years this formula has been used to “smooth” tension, calm irritability, and restore a sense of “free and easy” relaxation. It is a modification of a much older formula that addresses a similar pattern. [See Bupleurum & Tang Kuei Formula.] This version is most commonly applied when stress from external demands or tension causes one to tense up and develop mild nervousness, irritability or agitation.* The older version of this formula is used when there is tension without mild irritability or agitation.* This is the most popular Chinese herbal formula in use today.