The effect of electromagnetic radiation at frequencies (50, 100, 200 & 250 Hz) and intensity of 2 mT on the mortality of Rattus norvegicus norvegicus rat by oral administration of water exposed to this radiation for four hours was investigated. Effect of the sublethal frequency on the physicochemical parameters of water, count of bacteria in water and liver tissues of the rat were also studied. After one month of the experiment, the highest frequency 250 Hz recorded 80% mortality of rats. While, the lowest frequency 50 Hz not exhibited any mortality till the end of experiment. This sublethal frequency caused an increase in temperature, a decrease in total dissolved solids and no change in pH value, salinity, chlorinity and alkalinity of water. It showed also observed bactericidal effect against the water bacteria. It is significantly reduced the number of Escherichia coli and Serratia marcescens colonies and completely prevent the growth of Klebsiella pneumoniae, Pseudomonas fluorescens, Staphylococcus aureus and Staphylococcus epidermidis bacteria in comparing to the unexposed water (control). Destroying in the liver tissue cells was also recorded by this frequency.