A modified antiepileptic screening procedure to test anticonvulsant drugs is shown. Diphenylhydantoin sodium salt (DFH-Na) and phenobarbital (Phb) were tested throughout 8 h, at hourly intervals after a single oral drug intake in rats. Another group was tested at steady stage of DFH-Na during 7 days period. A single dose of DFH-Na was orally administrated to male and female rats (30 mg/kg) and after testing throughout 8 h: 0, 5, 28, 38, 52, 70 and 75% and 10, 18, 50, 35, 62, 50 and 70% protection against MES, was found. Only 20% protection was found in females to METsc test on the 6th and 7th h. However, 80, 60, 60 and 20% males were found protected against METsc test from the 4th to the 8th hour. Maximum blood serum levels were 2 micrograms/ml. Phenobarbital at doses 12 mg/kg in males and females as well showed: 30, 64, 66, 74, 84, 90, 40, 34% and 14, 36, 53, 41, 55, 70, 82 and 82% protection against MES, respectively. On the other hand, 60, 60, 46, 47, 94, 100, 80 and 20% and 80, 80, 46, 70, 60, 40, 80 and 20% of males and females were protected against METsc test, respectively. An average of 8 micrograms/ml and 12 micrograms/ml of Phb serum levels were found since the 1 to the 8th and 5th hours, correspondingly. A 28% protection of both male and female rats to MES test was found following 7 days of treatment with DFH-Na (30 mg/kg) treatment. Also an average of 10% female and males were found protected against METsc test.