The present study was carried out that preliminary phytochemical analysis and antibacterial activity was carried out in Strychnos nux-vomica against four selected pathogenic bacteria by disc diffusion method. The preliminary phytocompound such as carbohydrate, tannin and phenolic compounds, flavonoids and phytosterol shows the presence of chloroform, ethyl acetate and ethanol leaf extract of Strychnos nux-vomica. Where as in phytosterol compound is absent in chloroform leaf extract. In antibacterial activity, Ethanol leaf extract exhibit higher activity in Salmonella typhi when compared to Chloroform and Ethyl acetate leaf extract against Escherichia coli. In this Endeavour, traditional herbal medicines must perforce grant the benefits of modern science and technology to serve further global needs. The drugs derived from herbs may have the possibility of their use in medicine because of their good antibacterial activity.