There is provided a method for controlling the movement of bile and/or gall stones in the biliary duct. The method comprises gently constricting (i.e., without substantially hampering the blood circulation in the tissue wall) at least one portion of the tissue wall to influence the movement of bile and/or gallstones in the biliary duct, and stimulating the constricted wall portion to cause contraction of the wall portion to further influence the movement of bile and/or gallstones in the biliary duct. The method can be used for restricting or stopping the movement of bile and/or gallstones in the biliary duct, or for actively moving the fluid in the biliary duct, with a low risk of injuring the biliary duct.
