An anaesthetic vaporizer for dosing a liquid anaesthetic has a liquid container for the anaesthetic, and outlet tube from the liquid container to a dosing point, a first regulator for regulating a flow of anaesthetic from the liquid container toward the dosing point and a control unit for controlling dosing. To improve dosing and safety, the anaesthetic vaporizer has a return tube connected in parallel across the first regulator by a first connection point, downstream from the first regulator, and a second connection point, upstream from the first regulator, a second regulator is arranged in the return tube and a third regulator is arranged in the outlet tube, downstream from the first connection point. The control unit controls at least one of the regulators in dosing the anaesthetic.