To get out of chemical pesticides, law has a major role to play, in addition to the other sciences. Any public policy, to be implemented, must be transformed into legal rules. Unlike other social norms, the legal norm is recognised by institutions and guaranteed by the state system. However, law is not only regulation; economic norms (labels, contracts, taxes) are also part of it. So, how can legal decisions help to get out of pesticides? We will provide an answer in two stages. First, it is a question of knowing how the law integrates health and socio-economic considerations into its system. The relationship between law and other sciences is a part of the matter. Then, inside the law itself, what are the norms that allow to reduce the pesticides? What combinations of instruments should be favoured ?