 The efficacy of Botulinum toxin A BoNT-A in Asian population has not been properly studied and there is no literature available on the most efficacious dose of BoNT-A for sialorrhoea treatment. This research is aimed to find the dose of Dysport that would be efficacious without treatment-related adverse events and the duration of effectiveness of the drug for sialorrhea treatment in Malaysian patients. The efficacy, safety, tolerability and adverse effects of three doses of Dysport50MU, 100MU and 200MU are examined at 2,6,12 and 24 weeks post injection in this double-blinding, randomized trial. 