Abstract： Objective： To analyze the medication rules of Professor GUO Zhitao in treating mastalgia in the Lingnan region using data mining techniques. Methods：Case data of mastalgia treated by Professor GUO Zhitao at the outpatient department of Guangdong Provincial Second Hospital of Traditional Chinese Medicine from March 2019 to March 2024 were collected. Prescriptions were recorded， and a database was established. The Traditional Chinese Medicine Inheritance Computer System Platform V3.5 was used for data processing， including frequency analysis， meridian entry analysis， efficacy analysis， association rules analysis， and cluster analysis. Results： A total of 680 medical cases were included， involving 203 types of Chinese herbs. Twenty herbs had usage frequencies greater than 20%， with the top five being Leonuri Herba， Curcumae Radix， Glycyrrhizae Radix et Rhizoma， Citri Sarcodactylis Fructus，and Cyperi Rhizoma. The main meridian entries were liver，lung，spleen，heart，and stomach meridians. The primary functions of the herbs were blood-activating and stasis-resolving， deficiency-tonifying， and qi-regulating. Association rule analysis identified 17 core herb pairs，with the top three being Bupleuri Radix-Cyperi Rhizoma， Leonuri Herba-Perillae Caulis， and Leonuri Herba-Cyperi Rhizoma. Cluster analysis identified six core herb combinations. Conclusion： Professor GUO Zhitao's approach to treating mastalgia primarily involves bloodactivating and stasis-resolving， deficiency-tonifying， and qi-regulating herbs. The treatment principles include promoting blood circulation to regulate menstruation，soothing the liver to relieve depression，harmonizing the liver and spleen，and ensuring smooth flow of qi and blood. The selection of herbs is adapted flexibly to the characteristics of the Lingnan region.