The invention relates to an adjustable stomach band with a rigid back (4) and a chamber (2), arranged on the stoma side of the back (4), for control of stoma constriction by means of introduction or removal of fluid from the chamber (2). According to the invention, such a stomach band with a preferably automatic setting of the stoma constriction, depending on the food intake, is possible, whereby a second chamber (1) is provided to the stoma side of the back (4), directly connected to, or cooperating with the first chamber (2), such that the control of the stoma constriction is achieved by means of displacing the fluid between the chambers (1, 2) or between a reservoir (9) and the stoma-constricting chamber (2). An auto-regulation can be achieved, whereby a second chamber (1) is embodied as sensor for recording a pressure rise in the stomach and the control of the stoma constriction is achieved depending on the recorded pressure by means of displacement of the fluid from the chamber (1), or from the reservoir (9) into the stoma-constricting chamber (2).