Abstract: An appliance for the removal of body substance, in particular an ophthalmological vitrectomy device, uses a mechanical cutting edge or laser radiation (18) for detaching vitreous body material. Detached parts of vitreous body material (22) are suctioned off by an aspiration cannula (10). To avoid traction in the vitreous body material (12), a control system (C) for the time sequence, energy and length of the laser pulses (18) and for the suction pump (P) is provided. The control is effected in such a way that a volume (22) of vitreous body material suctioned through the opening (14) is in each case detached free of traction, by one or more laser pulses, from the remaining vitreous body material (12) located in the eye, before a further volume of vitreous body material is suctioned in. The exit direction of the laser beam pulses (18) from the radiation conductor (16) is transverse to the aspiration direction.