Pharmaceutical composition for treating oxidative stress induced pathology, comprising an association of the active ingredients methionine, cysteine and phenylalanine in association with at least one pharmaceutical excipient； said active ingredients being present in a methionine/phenylalanine molar ratio between 2.5 and 12.5； and in a methionine/cysteine molar ratio between 2 and 10.5； and the three active ingredients being present in free state, such as inner salt, or in the form of pharmaceutically acceptable salt； wherein said pharmaceutical composition is used for treating one of the oxidative stress induced pathologies, including intestinal system disorders, such as intestinal wall irritations, hemorrhoids of types 1, 2, 3 and 4 of Goligher classification. It is also disclosed the use of said composition in preparing a medication for treating oxidative stress induced pathology.
