The authors in a previous research verified the effect of administration of three non steroidal antiinflammatory drugs (piroxicam, naproxen, ketoprofen) on the glutathione levels in various organs of rat. On the basis of these researches, the authors study the effect of the same anti-inflammatory drugs on glutathione levels in rat brain, dissected in order to analyze separately the cortex, cerebellum and the remaining part of the brain. The obtained results show that the distribution of the three drugs is not homogeneous in the studied areas and that these three drugs act differently on glutathione levels. These facts let us suppose that piroxicam, naproxen and ketoprofen produce toxic events that are different according to the brain areas we studied.