YPFS (Yu Ping Feng San)

Within this formula, Huang Qi greatly supplements the lung and spleen qi, thus also the defensive qi. Hence the defensive qi is able to secure the exterior from attack by external evils. Bai Zhu fortifies the spleen and supplements the qi, thereby directly aiding Huang Qi. Fang Feng gently resolves the exterior. It expels any lingering wind evils without damaging the defensive qi. Although it is somewhat windy and acrid, unlike other exterior-resolvers, it does not damage yin fluids. This formula comes from Zhu Dan-xis Ming dynasty Dan Xi Xin Fa (Dan-xis Heart Methods) published in 1481.