In this study, we will determine whether treatment with L- Dihydroxyphenylserine (L-DOPS, Northera) in addition to dopaminergic drugs will improve postural stability and activity of daily living, and reduce fall risk and/or severity of falls in PD patients.Falls, early in PD (within 5 years of diagnosis) probably arise from slowed locomotion. Slowed locomotion is corrected by dopaminergic drugs, hence falls early in PD are decreased by such drugs. Later in PD (5 or years after diagnosis) falls, recurrent falls, occur despite such drugs. There is evidence that falls late in PD occur because of impaired postural stability which does not respond to dopaminergic drugs or may be made worse by such drugs. A single fall, although serious, may be only partly related or even unrelated to PD. "Serious fall" is defined as: all four limbs hit the ground, the skull hits the ground, or there is soft tissue or bone injury. However, some people with PD fall repeatedly. In such patients the role of impaired postural stability was stressed. Although the mechanisms underlying impaired postural stability are not well-known in patients with PD, attention is focused on the noradrenergic system. L-DOPS, a drug that enhances norepinephrine levels in the peripheral and central nervous systems, has been shown to moderate orthostatic hypotension, and often improve some PD symptoms.