Apparatus for treating a patient is provided, including an electrode device, which is configured to be placed in a vicinity of at least one gall bladder site of the patient selected from the group consisting of: a gall bladder, a neck of the gall bladder, a cystic duct, a hepatic duct, a common hepatic duct, a bile duct, a common bile duct, sensory fibers of the gall bladder, and a hepatic port. The apparatus further includes a control unit, which is configured to drive the electrode device to apply a current to the site, and to configure the current to induce weight loss of the patient. Other embodiments are also described.