Methods, devices and systems facilitate intermittent and/or partial obstruction of a pyloric valve. Devices generally include a support portion for preventing the device from passing through the pyloric valve and a tissue engagement portion for contacting tissue adjacent the pyloric valve to obstruct the valve. Some embodiments also include a positioning member extending from the tissue engagement portion for helping position the device for obstructing the valve. A retaining member may optionally be included on the distal end of the positioning member for further maintaining a position of the device in the stomach. Some embodiments are deliverable into the stomach through the esophagus, either by swallowing or through a delivery tube or catheter. Some embodiments are fully reversible. Some embodiments self-expand within the stomach, while others are inflated or otherwise expanded.