The work proposes to reexamine the athetesis and the emendations which were applied to diverse passages of Euripides' Medea, asserting that many of these are not necessary, if one understands the revenge as a decision whose method is not established from the beginning, but it is constructed gradually. This gradation provokes apparent contradictions. They are considered the following controverted passages: 40-43, 87, 261-2, 361-2, 366-7, 468, 725-6, 782, 785-6, 923-4, 1056-1080, 1121, 1220-1, 1316, 1359, 1387; and also all the play development, in order to prove the effect of those in the gradual construction of the revenge; it is taken into account the vocabulary use in the inside of the play. In this process, the passages here analysed, and discussed by the critics about his authenticity, result defensible and necessary to establish the graduation, which is verified in the inside structure, in the images and in the construction of the crime.