The invention relates to an expandable intra-gastric balloon (1) for treating obesity, the balloon being for implanting in the stomach in order to reduce its volume, said balloon (1) comprising a first flexible pouch (2) provided with first connection means (3) for receiving a connection member (6) that is for connection to a first fluid source in order to expand said first pouch (2) in the stomach by filling it with fluid, the balloon being characterized in that it includes at least one second flexible pouch (20) provided with second connection means (3'), said second connection means (3') being separate from the first connection means (3) in such a manner as to be capable of being connected to a second fluid source different from the first fluid source. The invention applies to treating obesity.