Phototherapy is a procedure that is applied to newborns who have jaundice, where their condition changes yellowish color in the skin and eyes of babies, it is due to excess bilirubin in the blood. Usually, it leaves the body through bowel movements. This happens because the baby's system breaks down the blood cells but does not eliminate bilirubin.
This technique is based on the ability of light to act at the level of the skin on bilirubin. This results in a photochemical excitation phase where bilirubin is transformed into other non-toxic (water-soluble) products when light is taken up by the skin, making them more easily excreted. Phototherapy is the treatment of choice for neonates with unconjugated hyperbilirubinemia; early initiation of this therapy decreases the likelihood of resorting to exchange transfusion, a more aggressive technique that can lead to major complications.