Objective To summarize the characteristics of clinical dosages of Baizhu（ Atractylodesmacrocephala）since Han Dynasty. Methods The most representative medical works since Han Dynasty were selected. Usages of Baizhu in these books were all recorded by Microsoft Office Excel 2007 to establish database of clinical dosages of Baizhu. The frequency

most common dosage

upper limit value of common dosage

lower limit value of common dosage

maximal dosage

minimal dosage

and average dosage of Baizhu were statistically analyzed. Results From Han Dynasty to Tang Dynasty

the usual dose range of Baizhu becomes smaller

the average consumption is basically unchanged

and the most commonly used quantity assumes the trend of escalation

dose range increased significantly.From Tang Dynasty to the periods of Song

Jin and yuan

dosage of Baizhu decreased. Today’s doctors always adopted small dose as their predecessors of Ming and Qing dynasties

while this does not mean the condition that high dose of Baizu are used has gone extinct. Conclusion From Han Dynasty to the present

Baizhu has tend to be used in large doses. Baizhu is used to dry dampness with its bitter and warm property in large dosage and used to tonify Qi with small dosage.