This chapter describes how concerned scientists and health professionals challenged the safety of pesticides in Argentina and Brazil respectively. It also describes the role of health professionals in support of grassroots movements fighting agrochemicals in Argentina. The chapter focuses on the lessons on the role of science and health professionals in the disputes over agrarian models and therefore agrarian futures, relevant issue in the global agenda of food security. The national congresses organized by Brazilian Association of Collective Health bring together around 7,500 health experts and professionals. Investigating how pesticides affect the survival and different biology traits of anuran amphibians is especially important considering the importance of amphibians in the food webs of diverse ecosystem communities, as well as biological indicators of environmental health. Regarding the former, social movements from the state of Ceara, region of fruit production for export, were fighting locally the effects of agrochemicals in the health of workers, communities, mothers, as well as the environmental contamination.