A growing body of evidence suggests pesticides may play a role in Parkinson’s disease (PD) in humans. Self­reported PD has been associ­ated with lifetime use of pesticides, and animal studies have suggested that the pesticides paraquat and rotenone can cause oxidative stress and mitochondrial dysfunction, respectively—posited mechanisms of action in PD—as well as symptoms in rodents similar to human PD. Now, researchers have linked human exposure to paraquat and rotenone with PD.