The invention describes a method for operating a controllable electromechanical brake booster and the corresponding brake booster which, via a coupling element between the brake booster and pedal rod, is capable of applying a force in opposition to the pedal activation force of a driver, and can therefore be operated as a pedal simulator. For this purpose, a pedal opposing force can be set by a characteristic curve as a function of a pedal position which is predefined by the driver, and can give the driver a pedal sensation even if there is no reaction of, for example, a conventional brake system. In a further operating mode, the brake booster can be operated in its original form.