Methamphetamine (METH) is a psychostimulant that affects central nervous system by increasing the concentration of the free dopamine, whose oxidation leads to the permanent damage in the structure and function of neurons, as the consequence of the increased production and accumulation of the radical oxygen species (ROS). By using Drosophila melanogaster as a model organism we have tested impact of an acute dose of volatilized METH (vMETH) on the concentration of hydrogen peroxide (H2O2), in the brain, as one of the ROS and redox status representative. Individual flies of wild type strain CantonS (wt) used in the experiment were exposed to vMETH using the FlyBong method. The concentration of H2O2 was measured in the head tissue extracts, 10 hours after the administration, using dihydroetidium florescent dye. The results have shown that the acute exposure to vMETH does not lead to the change in the concentration of H2O2 in the wt flies compared to the control group. Considering that research have shown connection between administration of the METH and increased expression of period (per) gene with enzyme activity of tyrosine hydroxylase, included in the synthesis of dopamine, I tested whether there is a difference in the concentration of H2O2 after the acute exposure to vMETH between different circadian mutants and wt flies. Circadian mutants of genes per, timeless (tim), Clock (Clk) and cycle (cyc) with alleles per01, tim01, ClkJrk and cyc01 were used in the experiment. per01 and tim01 flies showed the decreased concentration of H2O2 compared to the controls while ClkJrk and cyc01 flies had higher concentration of H2O2 after the acute exposure to vMETH. The concentration of H2O2 is significantly lower in tim01 flies compared to wt flies after the exposure to vMETH while cyc01 flies had a significantly higher concentration than wt flies. Based on the results of this thesis, we suggest the influence of circadian genes on the endogenous concentration of H2O2, which is in the absence of per or tim increased, and in the absence of Clk or cyc decreased compared to wt. The administration of vMETH potentiates the production of H2O2 in the absence of cyc while the absence of tim gene attenuates that effect. The lack of difference in wt flies is surprising and possible mistakes in the method or its use should be considered. By establishing the molecular pathways involving H2O2 and circadian genes new methods for treatment of addiction could be developed.