To investigate the formulation and medication characteristics of ancient and modern Chinese medicinal prescriptions in the treatment of pulmonary abscess.Methods:This study collected and sorted out ancient and modern Chinese medicinal prescriptions for treating pulmonary abscess included in Dictionary of Traditional Chinese Medicine and databases including China National Knowledge Infrastructure(CNKI)，China Science Periodical Database(CSPD) and Chinese Citation Database(CCD).SPSS Modeler software was used to analyze the association rules.SPSS Statistics software was used for system clustering and factor analysis.Results:A total of 361 prescriptions were enrolled，including 127 ancient prescriptions and 234 prescriptions in modern literature，involving 300 drugs.The core drugs of these ancient and modern prescriptions include Glycyrrhizae Radix et Rhizoma，Platycodonis Radix，Coicis Semen，Fritillariae Cirrhosae Bulbus，Trichosanthis Fructus，Mori Cortex，Armeniacae Semen Amarum，and Citri Reticulatae Pericarpium，which can clear the lung heat，resolve phlegm，evacuate pus，and expel the toxin.Ancient prescriptions mainly used Ginseng Radix et Rhizoma，Asparagi Radix，and Angelicae Sinensis Radix to reinforce healthy qi and eliminate pathogens.In modern literature，Houttuyniae Herba，Ionicerae Japonicae Flos，and Taraxaci Herba were primarily used for the purpose of clearing heat and removing toxin.The results of association rule analysis showed that the commonly used two-drug combinations included Glycyrrhizae Radix et Rhizoma-Platycodonis Radix，Coicis Semen-Semen Benincasae，and Ionicerae Japonicae Flos-Forsythiae Fructus.The commonly used three-drug combinations included Coicis Semen combined with Semen Benincasae and Persicae Semen，and Scutellariae Radix combined with Houttuyniae Herba and Platycodonis Radix.System clustering and factor analysis mainly resulted in the following combinations：a combination of Persicae Semen，Semen Benincasae，Coicis Semen，Phragmitis Rhizoma，Scutellariae Radix，Houttuyniae Herba，Ionicerae Japonicae Flos，Forsythiae Fructus，and Taraxaci Herba; a combination of Poria，Citri Reticulatae Pericarpium，Pinelliae Rhizoma，Trichosanthis Fructus，Anemarrhenae Rhizoma，and Mori Cortex; a combination of Glycyrrhizae Radix et Rhizoma，Platycodonis Radix and Fritillariae Cirrhosae Bulbus; a combination of Astragali Radix and Angelicae Sinensis Radix.Conclusion:The core drugs and drug combinations are dug out using methods such as association rules and system clustering methods，which can provide ideas and a basis for the clinical treatment of pulmonary abscess.