The crude powdered leaves of these plants were extracted by 70%ethanol. J. schimperiana leaf extract had higher amount of yield (11.29 %) than C. colocynthis leaf extract (8.28%). The total flavonoid was higher inJ. schimperiana leaf extract (7.89 + 0.379) than C. colocynthis leaf extract (4.84 + 0.248).The antioxidant activities of ethanol leaves extracts of J. schimperiana and C. colocynthiswere screened using ferric reducing power assay and 1.1-diphenyl-2-picryhydrazyl(DPPH). The reducing power of J. schimperiana and C. colocynthis ranged from 69.275+0.469-96.753+0.012 and 61.317+1.004-96.390+0.016 respectively.The J. schimperiana leaf extract also exhibited higher antiradical activity against DPPH (16.68+0.1869-92.36+0.1364) than C. colocynthis (11.87+0.0943 - 69.98+0.1037). The antimicrobial activity determination of 70%ethanol leaves extractsof J. schimperianaand C. colocynthiswere performed using two standard bacterial strain, Escherichia coli andStaphylococcus aureus. Inhibition zones (in mm) were ranged from 7.133+0.125-12.093+0.146 and 15.027+0.052 - 20.133+0.125 against S. aureus and E. coli respectively in different concentrations of J. schimperiana leaf extract.From the same concentration, C. colocynthis showed inhibitory activity S.aureusandE.coli ranged from 5.030+0.049-10.067+0.094 and 6.007+0.074 - 14.933+0.094 respectively. Therefore, the presence of the important phytochemicals in the plant leaves is a scientific justification of the use of the plant in the traditional treatment against various diseases. Key words: antimicrobial, antioxidant, Citrulluscolocynthis, Justicaschimperian