A trocar system with a trocar which has a trocar mandrel, a trocar sleeve and a valve block, characterized by a tubular working sleeve having an axially continuous inner channel, in which the trocar can be inserted in such a way that the trocar sleeve is sealed with the outer perimeter thereof in the inner channel, so that the distal tip of the trocar mandrel projects distally out of the working sleeve and that the valve block is located proximally outside the inner channel, and having at least one working channel which is formed on the working sleeve and extends from a proximal inlet opening to a distal outlet opening.