Objective: To analyze and summarize the prescription rules of professor XUE Bo-yu in treating patients with chronic hepatitis C. Method: All 149 cases of chronic hepatitis C treated by professor XUE Bo-yu were collected. The herbs meeting the inclusion criteria in the selected cases were recorded into Medcase V3.2 item by item. Association rules and cluster analysis were used to determine the use frequency of herbs in the prescriptions

common herbs combinations and prescription features

and explore the academic thoughts of professor XUE Bo-yu in treating patients with chronic hepatitis C. Result: The 149 medical cases were included in the study

involving 176 herbs. 26 kinds of herbs such as Salviae Miltiorrhizae Radix et Rhizoma

Rehmanniae Radix

Paeoniae Radix Rubra and Bubali Cornu were commonly used. According to association rules

the commonly used herbs combinations were ①Bubali Cornu

Salviae Miltiorrhizae Radix et Rhizoma

②Rehmanniae Radix

Paeoniae Radix Rubra ③Moutan Cortex

Salviae Miltiorrhizae Radix et Rhizoma

Bubali Cornu. Xijiao Dihuang decoction could be used as a basic prescription to treat chronic hepatitis C. Cluster analysis showed that the herbs commonly used were for clearing heat and detoxifying

activating blood and dissolving stasis

and considering other accompanying symptoms at the same time. Conclusion: Prescription rules of professor XUE Bo-yu in treating patients with chronic hepatitis C can be found out by data mining technique. It can provide a reference and objective basis for future clinical treatment.