Abstract: The rate of release of sodium and potassium ions by aqueous and ethanolic extract of leaves of Cassia occidentalis was investigated for some selected pathogenic bacteria in the genera Bacillus, Staphylococcus, Echerichia, Streptococcus, Klebsiella, Pseudomonas and Salmonella using flame photometer. The aqueous extract was found to be more effective in the leakage of Na+ and K+ ions than the ethanolic extract for all organisms investigated except Salmonella. The aqueous extract released 2.66 ppm sodium ions on Pseudomonas aeruginosa, whereas ethanolic extract released 13.3 ppm while the K+ ions released are 9.282 and 49.980 ppm for ethanolic and aqueous extract, respectively. It was found that only Salmonella typhii gives higher leakages of sodium and potassium ions for ethanolic extract than the aqueous extract. Comparison of the amount of Na + and K+ ions release by the plant extract with two commercial antibiotic (Chloramphenicol and tetracycline) showed that the latter gives a higher value than the former. For sodium ion, Bacillus substilis gives 167 ppm and 164 ppm for chloramphenicol and tetracycline respectively where as 2.28 and 3.42 ppm was measured for ethanorlic and aqeous extract of the Cassia occidentalis responsively. There was no significant difference in the amount of leaked Na+ ions and potassium ions between the two antibiotics. For Na+, Salmonella typhi has 164 ppm for chloramphenicol and 163 ppm for tetracycline while the value for Proteus vulgaris was 160 and 163 ppm, respectively.