The aminocompounds, which possess properties of weak bases, including amides, derivatives of urea and some aromatic amines do not interact during the nitrozation process with N2O3. These compounds interact with nitrozating agents at low pH levels, and undergo nitrozation through a different path, which include the interaction of the neutral substrate with hydrated or non-hydrated nitrozonium ions (NO+) and further formation of N-nitrozamides:H2O + NO+ + RNHCOR’ → RN(CO)COR’ + H3O+ Usually these reactions are very slow at pH>3, however the reaction’s rate increases drastically in acid conditions. It was established that secondary amines, N- alkylurea and N-Alkylcarbamates, which are weak bases, are nitrozated much easier than strongly basic secondary amines. The present work contains the investigation of the N-nitrozomethylurea (NMU) formation in simulated gastric juice and optimization of the conditions of the reaction with the purpose of inhibition of these process. Taking into account the possibility of formation of Nitrozomethyulurea from creatinine, the rates of the reactions of NMU generation from methylurea and creatinine have been compared. The creatine is present in fresh meat and fish, while the creatinine is the product of their dehydration during meat and fish cooking that involves drying, frying or smoking. The abstract of the experimental investigation has concluded that the process of nitrozation is pH dependent in the range 1-4. At pH =1 and temperature of 10oC the [NMU] =1.88*10-5 M while at pH =4 we get 0.34*10-5M. The process of nitrozation does not show a maximum of the reaction rate and decreases with the increase of pH. At the same time the NMU content at equilibrium was calculated and the results show that in dependence of the pH it varies from 4,5% at pH=4 to 35% at pH =1. In order to identify the mechanism of the process, the constants of the rates of nitrozation in the presence of different nitrozating agents (N 2O3, NO+) was calculated. These calculations allow the statement that the constants of nitrozation’s rate in the presence of N2O 3 is substantially lower than the constants obtained for the nitrozation by NO+ , therefore the process of nitrozation takes place as a result of acid catalysis. In order to diminish the content of NMU in the analysed system the following inhibitors were utilized: dihydroxyfumaric acid, it’s sodium salt and (+)catechine. As a result of the experimental investigation it has been concluded that dihydroxyfumaric acid has a greater inhibition capacity. The quota of nitrozated methylurea was calculated starting from it’s total initial concentration and it was found out that the content of formed NMU decreases from 33% to 16% with the increase of DFHNa from 1*10-5 M to 1*10-4 M.