Ethnobotanical Investigation has revealed that the roots of Thevetia peruviana and leaves of Parquetina nigrescens are being used to treat bacterial diseases. Phytochemical screening revealed the presence of alkaloids and terpenoids in both species. Agar well diffusion method was employed in the sensitivity test of the studied ethnobotanicals. Different concentrations (50, 100, 200 and 300mg/ml) of extracts of T. peruviana roots and P. nigrescens leaf extracts were employed against E. coli, Pseudomonas aeruginosa, Salmonella typhi, Staphylococcus aureus and Streptococcus mutans. All the organisms showed highest and lowest levels of inhibitions at 300mg/ml and 50mg/ml respectively. Leaf extract of P. nigrescens showed relatively more activities than the root extract of T. peruviana against the tested organisms. The Minimum Inhibitory concentration of both extracts also showed considerable activity at (50,100 and 200) mg/ml while the growth of the microorganisms was unrestrained at 25mg/ml.