Abstract: The invention relates to a recipient (1) for ex-vivo treatment of biological liquids, which includes: a rigid body (2); a reservoir (3) provided inside the body (2), which is formed by a side wall (4), a rigid upper wall (5) and a rigid lower wall (6) and has an internal thickness defined by the separation between the upper wall (5) and the lower wall (6), at least one of the upper wall (5) or the lower wall (6) having a window area (7) configured to allow the passage of electromagnetic radiation from outside of the body (2) to the reservoir (3); two ports (8, 9) for liquids to gain access to the reservoir (3) from outside of the body (2); and closure means (10, 11) for the ports (8, 9), the closure means (10, 11) being configured to provide, jointly, the reservoir (3) with hermetic sealing against gases and liquids.