A valve for distributing two fluids contained in a rigid flask by propulsion, the first fluid contained in a first flexible pouch, and the second fluid in the flask so as to be isolated from the first fluid before the fluid leaves through the valve. When the valve is placed on the flask, an internal part of the valve is inside the flask, an external part of the valve is outside the flask. A first passage which can be closed connects the inside of the first pouch and the space surrounding the external part of the valve, and a second passage which can also be closed connects the space intended to receive the second fluid and the space surrounding the external part of the valve. The valve has a second flexible pouch for receiving the second fluid, which is fixed to the valve and placed around the first pouch.