It is a Gram-positive, non-motile, non-spore forming coccus that occurs in chains or in pairs of cells. Investigatin of streptococci species from throat sample by blood agar plate method. Morphological and biochemical characterization of the throat swab culture was identifying the streptococci. Streptolysion O isolated from the group A beta haemolytic Streptococci has the ability to lysis the RBC’s which was confirmed by haemolytic assay. It was confirmed such as Bacitracin disc diffusion test, Catalase test and coagulase test. Streptolysin O toxin purification employed by ammonium sulphate fractionation method. After that total protein estimation followed by Lowry’s method.