Abstract: A method and a device for needleless injection of liquid into a substrate, in particular of a liquid pharmaceutical or cosmetic preparation into a biological tissue, which makes it possible in a particularly advantageous manner to reliably inject a particularly fine liquid jet into the substrate without a significant increase in the static pressure in the liquid during the injection process. According to the invention, this is achieved by first accelerating the liquid received in a liquid container together with the latter to an initial velocity before the movement of the liquid container is stopped again, while simultaneously ejecting the liquid from the liquid container through an outlet nozzle under at least partial retention of its movement. Preferably, the ejected liquid jet is set in rotation about its jet axis before it impinges on the substrate, so that the jet receives a helical movement and thus practically drills into the substrate without splashing away laterally.