Abstract: The present invention relates to a novel pharmaceutical composition comprising N-acetyl cysteine, wherein the composition releases N-acetyl cysteine in accordance with the United States Pharmacopea Standards (USP XXI, apparatus 2, 50 rpm) in an artificial gastric juice having pH 1.2 to an extent of less than 30% after 1 hr of exposure, and to less than 45% after 2 hrs of exposure, that it releases N-acetyl cysteine in accordance with the same standard in a phosphate buffer having pH 6.8 after 1 hr (3 hrs of total exposure) of at least 30%, and at most 100%, and in the same phosphate buffer of pH 6.8 after 5 hrs (7 hrs of total exposure) of at least 90%. The invention further comprises a method for treating symptoms as well as a method of preparing the composition.