This article is a reflection on the concept of “mental alienation” forged during the séc. XVIII, when the madness is known and recognized as a mental illness. The mental alienation is seen as a product of the practices that working on mental illness, interventions that working as institutional arrangements that produced and certain forms of “subjetivação”. It is proposed to think about the devices “alienadores” at the present time, especially medical pratices with respect to the subjectivity, including where the growing medicalization oh individuals indiscriminately.