OBJECTIVE: To explore the mechanism of retention enema with green and red powder in the treatment of ulcerative colitis（ UC） of left colon type by network pharmacology and molecular docking techniques. METHODS:Traditional Chinese medicine systems pharmacology database and analysis platform（ TCMSP）

Pub Chem

STITCH database and literature search were used to screen the active components of retention enema with green and red powder and predict the action target. And the intersection was obtained with UC targets obtained from Gene Cards

Drugbank and online mendelian inheritance in man（ OMIM） database. Cytoscape 3. 7. 2 software was used to construct the “drugcomponent-target”network and screen the main active components. String 11. 0 platform was used to output the proteinprotein interaction（ PPI） network and screen the core targets. Gene ontology（ GO） functional enrichment analysis and Kyoto encyclopedia of genes and genomes（ KEGG） pathway enrichment analysis were performed on the core targets by using Metascape genomes database. The active components

core targets and key pathways were correlated with each other

and the network diagram was drawn by using Cytoscape 3. 7. 2 software. Schr9 dinger software was used to complete the molecular docking. RESULTS: Sixty-nine kinds of active components were obtained

including 10 main active components

including quercetin

kaempferol

luteolin

β-sitosterol

formononetin

stigmasterol

indiyured and carbendine. There were 206 targets

including 142 targets related to UC and 27 core targets with AKT1

TP53

IL-6

MAPK3 and TNF

mainly acting on MAPK

IL-17

PI3K/Akt

TNF

Toll-like receptor

apoptosis and EBV infection and other signaling pathways

which could play the functions of intercepting the inflammatory response

maintaining the mucosal barrier

improving the intestinal blood supply

balancing the autoimmunity

adjusting the intestinal flora and antiviral infection. And the molecular docking results showed that the main active components bound well to the core target proteins. CONCLUSIONS: Retention enema with green and red powder in the treatment of UC through multiple components

multiple targets and multiple pathways

which provides an objective basis for further basic and clinical research and explores new ideas for the development of external medication of UC.