OBJECTIVE: To explore the pharmacologically active components in areca nut that induce oral submucosal fibrosis (OSF) and the possible mechanism. METHODS: The chemical components in areca nut were analyzed using Thermo QE plus liquid chromatography tandem high-resolution mass spectrometer and Compound discover 3.2 data processing software. The chemical activity of the top 20 compounds was analyzed based on Chinese Pharmacopoeia (2015), PubChem, Chemical book, and SciFinder databases. The potential active components, core targets, biological functions and signaling pathways affecting OSF were analyzed by network pharmacology. The targets of OSF were obtained by integrating Genecards and KEGG databases. The compounds acting on the targets were selected from the Systematic Pharmacology Technology Platform of Traditional Chinese Medicine (TCMSP), and the target-compound, compound-TCM, target-compound-TCM network was constructed. Molecular docking was used to analyze the component-target binding. Immunohistochemistry was used to examine the expressions of key proteins in the PI3K-Akt and MAPK pathways in clinical samples of OSF. RESULTS: The core intersection target genes between the top 10 active ingredients in areca nut extract and OSF involved mainly the PI3K-Akt and MAPK pathways. In the clinical samples, the expressions of PI3K protein decreased and the expressions p-PI3K, AKT1 and PAkt all increased significantly in OSF tissue, where increased JNK protein expression and enhanced activity of c-Jun and c-Fos transcriptional factors were also detected. The OSF patients had significantly elevated plasma levels of IL-6 and IL-8 compared with healthy individuals. CONCLUSION: The main active ingredients including arecoline, arecaine, and guvacine are capable of activating the PI3K-Akt and MAPK pathways to promote the expressions of inflammatory mediators IL-6 and IL-8 and induce collagen hyperplasia, thus leading to the occurrence of oral submucosal fibrosis.