The present study was carried out to investigate the antibacterial activity of Ocimum basilicum ethanolic extract in-vitro and in-vivo by inducing diarrhea in rat which was caused by oral administration of pathogenic Escherichea coli. From the results obtained, it could be concluded that ethanolic extract of O.B leaves at dose 200 mg/kg. BW. was more effective and safe in comparison with antibacterial agent and other O.B dose, this anti-diarrheal activity of O.B ethanolic extract may be due to its constituents of secondary metabolites alkaloids like (hyoscyamine and scopolamine), phenols like...