Catalases are enzymes composed of a protein and a prosthetic group made up of iron porphyrin. The aim of the present research, was to study the catalytic mechanism of catalase on organic hydroperoxides rather than on hydrogen peroxide, when operating in organic solvents such as decane or hexane. The investigation was performed using gas chromatography and amperometry to analyse the reagents and reaction products of the catalytic reaction of catalase on tertbutylhydroperoxide or on cumene hydroperoxide, carried out in decane. The analytical results pointed to the hypothesis that, in this case, the organic solvent is involved in the reaction. In the absence of other reducing agents, therefore, a small percentage of it is oxidized and this redox reaction presumably involves the molecular oxygen present in solution, the consumption of which is determined experimentally through amperometry. This interpretation was confirmed in the gas chromatograms performed by the appearance of new peaks formed as a result of the enzymatic reaction in decane which are presumably to be attributed to species derived from the oxidation of decane, such as decanol.