Objective To summarize the clinical dosage of Gegen（ Puerariae Radix） in ancient times from the Han Dynasties（ 2000 years ago） and provide a basis for formulating the clinical dosage strategy of Gegen. Methods The database of clinical dosage of Gegen in ancient times was established. The formulas containing Gegen in the most representative medical books were selected and the formula name

total dosage

dosage of Gegen

herb numbers in a formula

water consumption in decoction and method of administration were recorded. The frequency

the most common dosage

the upper limit of usual dose

the lower limit of usual dose

the maximum dosage

the minimum dosage and the average dosage of Gegen were analyzed. The dosage characteristics of Gegen in ancient times were analyzed. Results The dosage of Gegen was large before the Song Dynasty. The dosage of Gegen was gradually reduced from the Song Dynasty. Conclusion The common dose of Gegen is used to engender liquid

allay thirst

upbear yang

check diarrhea and outthrust papules. The large dose of Gegen is used to resolve the flesh

abate heat

free the channels and quicken the network vessels.