Since the TPS-1 medium description, by Diamond, for axenic cultivation of Entamoeba histolytica trophozoites, a spectacular advance in this parasite biology knowledge has been occurred. Recently we described a new medium, called PEHPS, which is as reliable as those of current use, and besides offers a more stable final density. From this latter, we developed, a new simpler medium, after being evaluated the specific contribution of several components of PEHPS. Yields as high as those obtained with the original medium were obtained after the following modifications, incorporated in the new medium formula: Osmolarity 318 +/- 6 mOsm/Kg, pH 6.8, redox potential -130 mV, regulated only with 1.0 g/l of ascorbic acid, glucose 3.75 g/l, instead of the original PEHPS characteristics, which are the following: Osmolarity 340 +/- 42 mOsm/KG, pH 7.0, regulated with both cysteine and ascorbic acid and 6.0 g/l of glucose. As the new medium supplementation with vitamins did not result in significative differences with respect to the non supplemented medium, we eliminated all of these from the final formula.