Hypersalivation (sialorrhea) is a common complaint of patients with neurodegenerative disorders such as Parkinson's disease or amyotrophic lateral sclerosis and a frequently disabling side effect of atypical antipsychotic drugs. Conventional treatment including oral anticholinergic or antihistamine medication is often limited by adverse effects and lack of efficacy. Over the past few years, several studies reported decreased drooling after injections of botulinum toxin into the salivary glands. This review describes the current state of treatment of sialorrhea with botulinum toxin.