In C. elegans models of Parkinson’s disease, metformin treatment (10 mM) significantly decreased 6-OHDA-induced dopaminergic neurodegeneration, inhibited α-synuclein aggregation in transgenic worms expressing human α-synuclein, and upregulated expression of the antioxidant gene sod-3. The gene discussed is SNCA; the disease is Parkinson disease.