The invention provides a device for extracorporeal photo-isomerization of bodily fluid containing bilirubin. The bodily fluid derives from a patient suffering from an elevation of unconjugated bilirubin. The device includes a sterile tubing which accesses the patients bodily fluids (especially blood), routes the fluid into an extracorporeal chamber within which irradiation of bodily fluids takes place, and returns bodily fluids to the patient. Bodily fluids are continuously circulated through a single length of sterile tubing using an adjustable pump to regulate the flow, and as the fluid passes into the extracorporeal chamber it is irradiated by blue light within the chamber with an emission wavelength range of approximately 450 to 530 nm. This irradiation induces a photochemical reaction in bilirubin that changes its structure and facilitates improved excretion of bilirubin once it is returned to the patient. The extracorporeal photo-isomerization turns the bilirubin into a more readily excreted form.