ABSTRACT
Some therapeutic effects of medicinal plants such as Achillea have been known for many years ago. In this investigation, the effects of methanolic extract of Achillea Wilhelmsii C. Koch on seizure induced by picrotoxin was studied in mice. This study was performed on animals pretreated with different experimental doses of percolated extract of Achillea Wilhelmsii via intraperitoneal injection and 20 minutes after extract injections, each animal received picrotoxin 10 mg/kg for induction of generalized tonic and clonic seizure. Latency of onset and duration of seizure, death time and percent of mortality were determined. The results showed that pretreatment of animals with different doses of extracts did not change the beginning time of seizure induced by picrotoxin. The duration of seizure increased [p<0.01], but the severity of seizures was milder than control group. In addition, all doses of extract lengthened the time of death [p<0.01]. The mortality rate was decreased with dose of 50 and 100 m a g [p<0.05, p<0.01, respectively]. The results showed that the dose of 100mg/kg is the most effective one. The extract of Achillea Wilhelmsii decreased the severity of generalized tonic and clonic seizure induced by picrotoxin and lengthened the death time; therefore it is a suitable for continuing investigation as anticonvulsant drug