Jade Windscreen Formula (Yu Ping Feng San) is a classical formula used to
increase the protective (wei) qi. It is used for people whose immune system is
weak, leaving them susceptible to catching colds. It can also be used for acute
attacks of wind-cold in patients who are too weak to tolerate dispersing formulas.
When taken in advance of the cold season, it can prevent colds, or in
extremely weak patients, result in less frequent or less severe colds.