The effects of ethanol on epilepsy are very complex. Ethanol can have depressant as well as excitatory effect on different animal models of epilepsy. Systemic administration of homocysteine can trigger seizures. The aim of the present study was to examine the changes of total spectral power density after ethanol alone and together with homocysteine thiolactone in adult rats. Adult male Wistar rats were divided into following groups: 1. saline-injected, (control) C; 2. D, L-homocysteine thiolactone, H (8 mmol/kg); 3. ethanol, E (E(0.5), 0.5 g/kg; E(1), 1 g/kg; E(2), 2 g/kg) and 4. E (E(0.5), E(1), and E(2)) 30 min prior to H, EH (E(0.5)H, E(1)H and E(2)H). For EEG recordings three gold-plated screws were implanted into the skull. Our results demonstrate that ethanol, when applied alone, increased total EEG spectral power density of adult rats with a marked spectrum shift toward low frequency waves. In EH groups, increasing doses of ethanol exhibited a dose-dependent effect upon spectral power density. Ethanol increased EEG spectral power density in E(0.5)H and E(1)H group, comparing to the H group (p > 0.05), the maximal increase was recorded with the lowest ethanol dose applied. The highest dose of ethanol (E(2)H) significantly decreased total power spectra density, comparing to the H group. We can conclude that high doses of ethanol depressed marked increase in EEG power spectrum induced by D,L-homocysteine thiolactone.