The bleach (Sodium hypochlorite) is commonly uses in the hospitals for disinfeciton of the surfaces and equipments, and rarely uses as antiseptics. The concentration of sodium hypochlorite in the commercial bleach usually about 5% (50,000 ppm). Although review of the different references indicates differences in the concentrations and in the exposure times of bleach, it is commonly effective against vegetative bacteria in 100 ppm (1/500 dilution) for ten minutes, M.tuberculosis and spore-froming bacteria in 1000 ppm (1/50 dilution) for ten minutes. In the presence of organic substances such as sputum, blood, the bleach should be prepared ten fold concentrate than the advised concentration. In case of presence of the viruses (HIV, Hepatit B) in the rich media such as blood and serum, the advised bleach concentration is 5000 ppm (1/10 dilution), the exposure time ten minutes. The concentration of bleach for fungi varies depending on the genus of the fungi , for Aspergillus niger is 100 ppm for 60 minutes and for the rest of fungi is 100 ppm for five minutes. It is reported that 100 ppm for 90 minutes exposure time is sufficient for protozoa.