In the present study, we has been isolated the anti-cariogenic component, stigmasterol, from Aralia continentalis (A. continentalis) and identified by MS, $^1$H-NMR and $^{13}$C-NMR and also investigated the anti-cariogenic properties of stigmasterol. The methanol extract of ,A. continentalis showed concentration-dependent inhibitory activity against the growth and acid production of S. mutans. The MeOH extract was suspended in H$_2$O and sequentially partitioned with n-hexane, CHCl$_3$, EtOAc, and n-BuOH. The CHCl$_3$ fraction showed remarkable antibacterial activity against S. mutans. The anti-cariogenic compound, stigmasterol, has been isolated successively through the screening system and various chromatography methods. Anti-cariogenic properties of stigmasterol were also investigated. From this active chloroform subfraction, isolation and identification finally gave (24E)-stigmasta-5,22-dien-3${eta}$-ol (stigmasterol) {[a]$_D;^{25}$ -48.33$^{circ}C$(C 0.28, CHCl$_3$)} by spectroscopic methods (MS, $^1$H-NMR and $^{13}$C-NMR) as an active principle. The compound, stigmasterol, showed significant growth, acid production, adhesion and water-insoluble glucan synthesis inhibitory effect against S. mutans. These results suggest that stigmasterol from ,A. continentalis may inhibit cariogenic properties of S. mutans and these properties may provide some scientific rationales that the local inhabitants used the extracts for treatment of dental diseases.