Electromechanic brake booster

For forming an anti-rotation device, a region of the linearly guided component of the threaded spindle/threaded nut arrangement is provided with a cylindrical guide profile, which interacts with a complementary profile that is fixed relative to the housing (14). The area of the guide profile has such a shape that the linearly guided component is supported against the complementary profile during a transmission of supporting forces that is uniformly distributed over the periphery of the cylindrical guide profile. An independent claim is also included for a motor vehicle brake system.