RESUMO
Based on the ancient Chinese medical literature and modern clinical application literature， Mahuangtang was systematically analyzed， including its origin， composition， processing requirements and others， in order to provide support for the development of this famous classical formula. It was found that there were some doubts about Mahuangtang， such as the original variety， the processing of decoction pieces， and the dose conversion ratio. On the basis of fully considering the actual needs of the development of famous classical formula preparations and the usage habits of modern clinical practice， the development suggestions of the author were as follows：Ephedrae Herba should be selected Ephedra sinica without removing knots， Cinnamomi Ramulus should be selected from Cinnamomum cassia， Glycyrrhizae Radix et Rhizoma should select Glycyrrhiza uralensis and be roasted with honey， and Armeniacae Semen Amarum should be selected as Dan-processed products. The total dose of Mahuangtang was 24 g after conversion according to 1 Liang equal to 3 g as following the transition phenomenon and law. The preparation and usage method was as follows：took 1.8 L of water， first added Ephedrae Herba in water for decocting， evaporated 400 mL of water， removed the upper foam， then added the other three drugs， cooked over gentle heat to 500 mL， filtered the residue， took three times a day， about 160 mL warm decoction once. The major function recorded of Mahuangtang in ancient books was exterior sthenia syndrome of exogenous wind cold， it often used in the clinical treatment of cold， acute bronchitis， bronchial asthma and other diseases through the flexible application of the later doctors.