The present invention relates to a device for injecting at least one chemical substance and/or preparation into trees and/or palmaceae, that includes: a) a vessel with an elastic container located inside said vessel, the elastic container containing the chemical substance and/or preparation at a pressure between 1 and 1.8 bars; b) a connecting element adapted to be introduced into the tree or palmaceae trunk by at least one of its ends; and c) an adapter system located at the outlet of the vessel, which comprises a non-return membrane, a membrane-carrier element, and a closing element of said adapter system, the adapter system allowing single or multiple dosages of the elastic container with chemical substances and/or preparations through the non-return membrane, and the coupling to the connecting element by a second end thereof.