Jade Windscreen Formula is a Classic Formula to Increase Qi (wei) Protector. It is used in people with their weak immune system leaving them susceptible to catching flu. It can also be used for acute cold wind attacks in patients who are too weak to tolerate dispersive formulas.
Taken as a preventive measure can prevent flu, or in extremely weak patients, results in less frequent and less severe flu. Pinyin: Yu Ping Feng San

Action according to traditional Chinese Medicine: Tones qi, stabilizes the outside and ends sweats.

Composition:
Atractylodis Macrocephalae Rhizoma (White Atractylodes Rhizome / Bai Zhu) 40% 
Radix Saposhnikoviae (Siler / Fang Feng) 40%
Astragali Radix (Astragalus / Huang Qi) 20%