Abstract: Pharmaceutical compositions containing unit or separate dosages of 2.5 to 5 grams of reduced glutathione (GSH) and known anti-tumor agents, to be used simultaneously, separately or sequentially in anti-tumor therapy.Compounds of the invention, that can be used both in mono- or polychemotherapy, reach surprising results against tumors, thus avoiding the onset of dangerous side-effects, such as nephrotoxicity induced by cisplatinum, and increasing the long term survival rates.