Sialorrhea may present as a troublesome symptom in patients suffering from Parkinson's disease. Current options for treatment include anticholinergic drugs, irradiation, surgery, oral-motor and behavioural therapies, and injection of botulinum neurotoxin (BoNT) in the salivary glands. The aim of this study is to evaluate the safety and administration of BoNT as a treatment for sialorrhea in patients with Parkinson's disease (PD) based on a review of the studies conducted so far in this field. A PubMed search was conducted using the major keywords sialorrhea, botulinum neurotoxin, botulinum toxin and Parkinson's disease. The literature search identified 12 articles, which were selected for further analysis. Few adverse effects were described in the studies included in this present review. Various treatment strategies, including different medication dosages, were applied in the studies. BoNT treatment is safe for sialorrhea in patients with PD. Positive effect is well documented, and there have been relatively few reported adverse effects, which have been mild and transient. Based on this review, a treatment algorithm is proposed. Ultrasound guidance may not be necessary when injecting the parotid gland but may improve the effect and safety of administration, especially when injecting the submandibular glands.