An NO-accumulation apparatus, method and use, comprising: a container (120) defining a cavity for accommodating a liquid (105), an inlet (150) for feeding the liquid into the container (120) and an outlet (151) for delivering the liquid from the container (120) to a bath unit; an NO-gas dissolving unit (140) for dissolving gaseous NO in the liquid (105) to produce an NO-containing liquid, wherein the NO-gas dissolving unit (140) is arranged in the container (120) and/or forms a part of the container (120); and an NO-gas port (110) in fluid communication with the NO-gas dissolving unit (140), wherein the NO-gas port (110) is adapted for coupling, particularly for releasably coupling, with an NO-gas supply, whereby the apparatus further comprises means for decoupling the inflow of NO to the liquid (105) within the container from the removal of the NO-containing liquid (NO-decoupling means), so that the removal of the NO-containing liquid is inhibited, when the NO is flowing into the liquid, and also the NO inflow is inhibited when the NO-containing liquid is removed from the container (105).