Objective: To identify people’s way of acting after the diagnosis of tuberculosis, through their social representations about the disease. Method: Qualitative and descriptive study based on the Theory of Social Representations, in which 23 patients of a school health center in Belém, PA, Brazil, participated. The software ALCESTE was used to generate a class concerning the impact of the diagnosis in people’s lives. Results: The dimension of a new reality caused by the diagnosis of tuberculosis is linked with the image of dirt, (process of objectification) communicable/mortal disease that exclude, causing sorrow, despair and revolt (dimension of the affections), reverberating in the patients’ actions (dimension of action). Final considerations: global knowledge about tuberculosis, linking the knowledge of everyday life with the reified universe, pointing the multidimensionality of the phenomenon. The conclusion is that investing in the deconstruction of archaic beliefs about the tuberculosis that kills, replacing it with the curable tuberculosis, is necessary.