Abstract: The invention concerns a device for the extracorporeal irradiation of a patient's (P) bodily fluid containing bilirubin, comprising a first (10) and a second (12) line which can be connected to the patient (P), an impermeable irradiation unit for bodily fluids (14) connected therewith and located between the first (10) and the second (12) lines, and at least one adjustable feed unit for bodily fluids (16) located in the first (10) and/or the second (12) line, wherein by means of at least one feed unit for bodily fluids (16) an adjustable flow of bodily fluid through the lines (10, 12) and the irradiation unit for bodily fluids (14) is achievable, in which the first line (10) is designed to continually circulate the bodily fluid drawn from the patient (P) and route it to the irradiation unit for bodily fluids (14), and the second line (12) is designed to continually circulate the irradiated bodily fluid to the patient (P), and in which the irradiation unit for bodily fluids (14) contains an radiation source fo