The present invention relates to a device for the preparation of a product to be infused in a subject.The device comprises:- at least two containers (1a) and (1b),- at least one means for generating a flow (2a) able to control the quantity of fluid to flow,- at least one redirection means (3a),wherein said redirection means selectively allows a fluid communication between said container (1a), and said means for generating a flow (2a) and between said means for generating a flow (2a) and container (1b).
