Patients with PD have exceptionally poor sleep. Sleep in patients with PD is characterized by excessive activity in surface electromyographic (EMG) recordings from many different muscle groups. Despite sleep disturbances, approximately 50% of patients experience a transient (1 to 3 hour) reduction in waking motor symptoms upon arising in the morning. This effect has been termed Sleep Benefit. This study will evaluate the effects of valerian, a medicinal herb, on the sleep of patients with PD.