Gegen huangqin huanglian decoction is a famous prescription of Treatise on Febrile Diseases. Gegen sheng qing yang， diaphoresis， sheng jin and disperse lung to make upper jiao smooth. Its application embodies the theory that cleaning source so that flow of self-cleaning and the exterior interior relationship of lung and large intestine. Hungqin and haunglian check and clear heat with dampness. Its application embodies the theory that dampness should be rushed down lightly and xie Qi should be rushed down as soon as possible for saving yin jin. The decoction treat of lung and large intestine at the same time. It has the important guiding significance for diagnosis and treatment of lung， intestinal diseases and disease of dampness heat.