A method of operating an adjustable roll stabilizer (1) of a motor vehicle. The adjustable roll stabilizer (1) has an actuator (2) which can be rotated through a system angle (α) relative to a rotational axis (3) in order to twist two stabilizer sections (6a, 6b), connected thereto, relative to one another. The stabilizer sections (6a, 6b) are each a radial spaced away from the rotational axis (3) and each is coupled to a wheel suspension (7a, 7b, 8a, 8b, 9a, 9b). The method includes controlling the actuator with a field-orientated regulator (20) as a function of input signals which include at least a target motor torque (21), and checking the control of the actuator (2), brought about by the field-orientated regulator (20), for plausibility independently of the field-orientated regulator (20).