Abstract: This invention relates to a device to reduce pulsations on a hydrostatic positive displacement units, such as an axial or radial piston machine working both as a pump and as a motor with a reversible direction of rotation. In the displacement units, at least one piston is mounted so that it can move longitudinally in a cylinder bore which forms a cylinder chamber. The device has a buffer element which is in communication with the high-pressure side and can be brought into connection with the cylinder chamber. The device reduces pulsations on hydrostatic positive displacement units by which the reversing actions of the cylinder chambers are optimized and the pulsations are effectively minimized in a broad bandwidth of operating conditions. A switchable valve, in particular a non-return valve which opens toward the cylinder chamber is located in a connecting channel between the buffer element and the cylinder chamber.