An implantable apparatus and a method for controlling fluid flow within a host body, for example for use as an incontinence device. A constricting member is provided for reducing fluid flow within a body canal when in a closed position, and for allowing fluid flow within the body canal when in an open position. In addition, there is a control mechanism for controlling movement of the constricting member between said open and closed positions. A link member links the constricting member and the control mechanism such that the constricting member and the control mechanism are implantable in different parts of the host body. A coupling for selectively transmitting axial movement to the link member may be provided between the link member and the control mechanism so that the constricting member cannot apply a damaging amount of force to the body canal.