Abstract: Sialorrhea is one of the common non-motor symptoms in patients with Parkinson's disease (PD). Local salivary gland injection of botulinum toxin type A (BoNT-A) can effectively alleviate this symptom. This article systematically reviewed the current research status of local salivary gland injection of BoNT-A for the treatment of PD-related sialorrhea and analyzed its efficacy from multiple dimensions. On this basis, it delved into the potential microbial effects of this therapy and innovatively proposed that local salivary gland injection of BoNT-A may alter the oral and intestinal microbiota composition, regulate the oral and intestinal microenvironment, and ultimately intervene in the key pathological pathway of PD (α-synuclein aggregation). This hypothesis provided a new direction for exploring synergistic treatment strategies for PD symptom management and disease delay.