There is no drug currently in clinical use that has more therapeutic indications and spanning more medical specialties than botulinum toxin (BoNT). Although increasingly used for cosmetic purposes, its worldwide utilization is still mostly for a variety of disorders associated with involuntary muscular contractions, abnormal secretion, and a variety of autonomic symptoms. Many of these symptoms are experienced by patients with neurodegenerative disorders, such as Parkinson's disease (PD), the second most common neurodegenerative disorder (after Alzheimer's disease). In addition to the classic motor symptoms, such as bradykinesia, tremor, rigidity, and postural instability, PD is associated with a large variety of non-motor symptoms (Jankovic, JNNP 2008, in press). BoNT has been found useful in many of the motor symptoms associated with PD, such as hand and jaw tremor, cervical, trunk and limb dystonia, blepharospasm, apraxia of eyelid opening, bruxism, camptocormia, freezing of gait, as well as in non-motor symptoms such as sialorrhea, seborrhea, hyperhidrosis, overactive bladder, and constipation (Sheffield and Jankovic, J. Expert Rev Neurotherapeutics 2007;7:637–647). BoNT may be the treatment of choice for many of these symptoms as the conventional dopaminergic drugs are of usually limited or no benefit, particularly for the non-motor problems. This review will focus on evidence-based studies for these various indications, highlighting the broad spectrum of disease-oriented, clinical utility of BoNT.