Glutathione levels are significantly reduced in peripheral blood mononuclear cells and red blood cells isolated from tuberculosis patients. Treatment of blood cultures from tuberculosis patients with N-acetyl cysteine, a glutathione precursor, was associated with improved control of intracellular M. tuberculosis infection. N-acetyl-cysteine treatment decreased the levels of IL-10, IL-6, TNF-alpha and IL-1, in blood cultures derived from tuberculosis patients, favoring the host immune cells to successfully control M. tuberculosis replication.