Paraquat, a herbicide widely used in agriculture for better crop production, is an environmental toxin and causes oxidative stress-induced systemic damages in plants, animals and humans. Epidemiological studies report that paraquat toxicity is related to the onset of parkinsonism in humans. Animal experimentations indicate that paraquat toxicity causes the cellular and molecular changes associated with parkinsonism. Experimental evidences show that bloodbrain-barrier limits the paraquat entry in brain of primates and humans and therefore, the doubts remain for a direct paraquat-induced parkinsonism in human. To define a remedial measure, extensive studies are required on the cause and prognosis of Parkinson’s Disease induced by such environmental toxicant.