A device (1) for opening bags in mixtures of wastes has a first group of tearing elements (2) for transferring tearing forces to bags and a second group of tearing elements (2) for transferring tearing forces to bags. A drive power can move the groups of the tearing elements (2) in such a manner that relative movement between tearing elements (2) of different groups can generate tearing forces. The device has a drive control device configured to control the drive power of at least one group of tearing elements (2) as a function of the operating situation.