Biology and medicine for cleaning biological fluids. A system for correcting a biological fluid includes a sealed container for a magnetically operated absorbent (MOA), a sealed chamber for mixing the absorbent with a biological fluid and for the absorbent precipitation therefrom, and a sealed filtering unit. The chamber and container are embodied so that they can modify the volumes thereof, have a common interchamber partition-wall fixed to the bottom and are interconnected through a passage embodied in the wall. The other sidewalls of the chambers have corrugations which form bellows. Lids of the chambers are pivotally connected so that they are pivotable around the pivot axis. The MOA container is arranged inside the absorber-mixing chamber and embodied as a bellow. An inlet connection is simultaneously connected to the inside cavities of the absorber-mixing chamber and to the container thereof.