This paper is a textual research about primitive dose of classical prescriptions in Treatise on Cold Pathogenic Disease（ 伤寒论）. Decocting technologies of classical prescriptions are analyzed comprehensively

such as herbs

water adding volume

amount of decoction obtained

decocting duration required

decocting times. Seven classical prescriptions were chosen as research object

including Gegen Qinlian Decoction（ 葛根芩连汤）

Chaihu Guizhi Ganjiang Decoction（ 柴胡桂枝干姜汤）

Baitouwen Decoction（ 白头翁汤）

Lizhong Decoction（ 理中汤）

Linggui Zhugan Decoction（ 苓桂术甘汤）

Ganjiang Huangqin Huanglian Renshen Decoction（ 干姜黄芩黄连人参汤）

etc.This research set 1 liang（ 两） as 3 g（ low dose）

9 g（ medium dose） and 13. 8 g（ high dose） respectively.Combined with primitive decocting method

the decoction effect were compared and researched. Results showed that decocting technologies affected the dissolution of related material composition. So did prescription dose. Adopting primitive decocting method

calculating herbs doses of classical prescriptions

when 1 liang equaling to 9 g

the decocting rate of active ingredient of crude herb pieces was top and the availability of herbs was most. Therefore

classical prescriptions could be used clinically with 1 liang amounting to 9g according to present crude herb pieces.