It is considered that the fundamental pathogenesis of pediatric pertussis lies in the dysfunction of lung

qi

， and it is advocated to treat the disease with the method of regulating

qi

and relieving cough. Clinically， the disease is divided into three stages for syndrome differentiation and treatment， initial coughing stage， spasmodic coughing stage， and prolonged coughing stage. In the initial coughing stage， the pathogenesis involves invasion by external pathogens and failure of lung

qi

to disperse； the treatment principle is to release the exterior， expel pathogens， ventilate the lungs， and relieve cough. For cold patterns， modified

San'ao Decoction

（三拗汤） is prescribed； for heat type， a self-formulated

Qingqi Xuanfei Decoction

（清气宣肺汤） is used. In the spasmodic coughing stage， the pathogenesis is the congealing of phlegm and fire with impaired lung purification； the treatment focuses on eliminating phlegm， dredging the meridians， purging the lungs， and relieving cough. Mild cases are treated with a self-formulated

Tongluo Xiefei Decoction

（通络泻肺汤）， while

severe cases are treated with a modified combination of

Maxing Shigan Decoction

（麻杏石甘汤） and

Qianjin Weijing Decoction

（千金苇茎汤）. In the prolonged coughing stage， the pathogenesis involves the depletion of

qi

and

yin

and latent pathogens in a weakened lung； the treatment aims to tonify

qi

， nourish

yin

， moisten the lungs， and eliminate residual pathogens. For lung

yin

deficiency， modified

Shashen Maidong Decoction

（沙参麦冬汤） is used； for lung-spleen

qi

deficiency， a self-formulated

Jianpi Gufei Decoction

（健脾固肺汤） is prescribed.