Abstract: Thiols such as N-acetylcystein (NAC) are used to replenish glutathione (GSH) level, with regard to their function in the maintenance of cellular reduction-oxidation balance and control of oxidative stress. Thiols play a role in the reductive metabolism of nitrates to NO, an important signaling molecule in the cardiovascular system as well as other systems throughout the body. This study aimed to evaluate the influence of NAC on decomposition of different organic nitrate esters according to its potential i.e., pentaerythrityl tetranitrate (PETN) and isosorbide dinitrate (ISDN). The results showed that NAC gives a rapid and significant decrease of PETN and ISDN during the incubation period. During the experiment, about 85% of PETN were decomposed, while the decomposition of ISDN was about 20%. Detection of nitrite and elucidation of disulphide bond of NAC gives evidence that confirms the presence of reactions.