In 1926 for the first time Dobell and laid low synthesized and used Hsre+ s ( horse serum, ringer, egg+ starch rice) as a culture medium for growth of E.histolytica. since then this medium along with tens of other media have been used for growth of E.histolytica and other intestinal microorganisms. This medium has been used worldwide in many diagnostic and research laboratories. In Iran, in the past two decades they have used this medium in the school of public health and Institute of public health research. Rezaeian and (1989) simplified the original formula by not using the albumin of the egg and they found the same efficiency for the cultivation of Amoeba in HSr+ s medium. Since Oct.1996 , we have used HSr+ s medium for cultivation and diagnosis of Entamoeba histolytica. Eighty five percent of stool culture with Entamoeba ( cyst or trophozoite) have been positive, furthermore E. histolytica were cultured in the medium, with the average growth rate of 100000/ ml which indicates an efficient growth rate.