This study examines the effect of thiamine (TH) and thiamine pyrophosphate (TPP) on epileptic episode model induced in rats with caffeine. Animals were divided into groups and given TH or TPP at doses of 10, 30 or 50 mg/kg intraperitoneally. Subsequently, all animal groups were injected intraperjtoneally with caffeine at a dose of 300 mg/kg. Time of onset of epileptic episode was recorded, and the latent period was calculated in seconds. At the end of the experiment, tGSH and MDA levels and SOD and MPO enzyme activities in extracted brain tissues were measured. Latent period duration in rats in the control group was 134 +/- 3.2 s, compared to 144 +/- 13.9, 147 +/- 14.5 and 169 +/- 15.1 s, respectively, in the TH10, TH30 and TH50 groups and 184 +/- 8.54, 197 +/- 9.1, 225 +/- 8.37 s, respectively, in the TPP10, TPP30 and TPP50 groups. Latent period duration was 236 +/- 6.7 in the diazepam group. Oxidant products were significantly lower in the TPP10, TPP30, TPP50 and diazepam groups compared to the control group (P < 0.05), while SOD activity and tGSH levels were significantly higher (P< 0.05). There was no significant difference between the TH10, TH30, TH50 groups and the control group in terms of oxidant and antioxidant levels (P > 0.05). In conclusions, TPP, especially at a dose of 50 mg/kg, significantly prolonged the latent period from administration of caffeine to time of episode and prevented oxidative damage. (C) 2013 Elsevier B.V. All rights reserved.