Introduction. The influence of antipsychotic medication on brain alterations in proton magnetic resonance spectroscopy (1H MRS) in schizophrenia can be the explanation of many discrepancies observed in the previous papers. Aim. The aim of this study was the evaluation of antipsychotic medication effect on the metabolite levels in the brain of schizophrenic patients based on 1H MRS examination. Methods. The group of 32 patients with a diagnosis of schizophrenia according to DSM -IV and 26 healthy controls were included into the study. The patients were examined twice - once after the period of at least 7 days without neuroleptics (baseline) and for the second time at least 4 weeks after stable doses of neuroleptics (follow-up). 21 patients were receiving risperidone and 11 - olanzapine. Proton resonance spectroscopy was performed on a 1.5 MR scanner. Each volume element (voxel) was localised in the left frontal lobe, in the left temporal lobe and in the left thalamus. Metabolite ratios: N-acetylaspartate (NAA) to creatine (Cr) and unsupressed water signal were analysed. Results. We found the significant increase of the NAA/Cr level in the thalamus in the group of patients treated with risperidone, we didn't observe similar changes in the olanzapine group. Conclusions. Our results confirm that the neuroleptic drugs, especially atypicals, modify brain metabolism measured by 1H MRS. The pattern of the changes suggest a possible neuroprotective influence of the antipsychototic treatment in schizophrenic patients. The small group of the olanzapine treated patients doses not allow to make any conclusions regarding this type of medication.