The aim of this study is to assess The Impact of Valerian Root Extract On PreMenstural Syndrome Severity of Symptoms. Inclusion criteria: Single, 18-35 years,Having regular menstrual cycles and normal 21-35 and Duration of 7-3 days in the last 6 months, Lack of physical and emotional illness known And use of a Use of certain medications,no Occurrence of stressful events during the 3 months before study And diagnosis of premenstrual syndrome according to the Daily Form, Failure to participate in research studies of similar. Exclusion criteria of the study, Lack of volunteers willing to Continued drug use,Occurrence drug allergies, Stopping the medication for a week in the first cycle and irregular use of medication in cycles 2 and 3 for two days,Understanding of physical and mental illness during the study, Married during the study, Relatives death relatives and had surgery during the past two months. This study was conducted on 100 students at dormitory of University - Tonekabon Branch. Students initially recorded daily symptoms for two menstrual cycles completed. Students with random assignment to treatment groups (capsule Sedamin 530 mg) and placebo control groups. Each student taking the drug daily for three consecutive menstrual cycle taking two last seven days And her symptoms were recorded daily symptom questionnaire. Consequence of this Study for the students is the reduction of the severity of mental, physical and behavior symptoms of premenstrual syndrome.