Abstract: Objective To explore the potential adverse reactions of Sennae Folium in constipation patients with breast cancer based on the bioinformatics and warn the risks so as to provide reference for the research on rational use of drugs in constipation patients with breast cancer.Methods of bioinformatics were employed.The microarray data of GSE85871 was downloaded from GEO database,and analyzed by means of gene ontology annotation,Kyoto Encyclopedia of Genes and Genomes pathway analysis and protein-protein interaction networks.Results The analysis showed that when used in constipation patients with breast cancer,Sennae Folium might lead to melanosis coli,along with abnormalities of appetite,cell signaling,carbohydrate metabolism,inflammatory response,myocardial contraction and mood,thus affecting the development of breast cancer.Conclusion It is recommended that close attention should be paid to the body state of patients related to digestive,nervous,immune,cardiovascular systems and carbohydrate metabolism.Clinicians should keep track of the development of patients' preexisting disease.

Key words: Sennae Folium, sennoside A, MCF7, early warning of risks, bioinformatics technology