An ingestible gastric volume reduction device (100) is provided that is controllably adjustable between an expanded state and a contracted state. A control subsystem within the device is able to selectively transition the device between both states. Such control can be by way of a biological or chemical sensor (102) in the device, a wireless (RF) receiver (104), or timer. Thus activation of the device whether to expand and fill a gastric volume or to contract to open up the gastric volume may be achieved from internal control (within device) or external control (to the device). The device may be used for patient treatment, by administering the device (e.g., through ingestion) to a gastric region and then controllably increasing and/or decreasing the volume of the device during treatment.