Bilirubin encephalopathy is the clinical and subclinical manifestations of neurological abnormalities caused by free bilirubin passing through the blood-brain barrier and entering the central nervous system, which leads to neuronal toxicity and degeneration, and is also called bilirubin toxic encephalopathy. For decades, kernicterus has been synonymous with bilirubin neurotoxicity. Strictly speaking, kernicterus is an anatomical term. From the perspective of pathological anatomy, the yellowing of brain tissue seen with the naked eye is used as the standard for kernicterus, thus reflecting the invasion of brain tissue (mainly nerve nuclei) by bilirubin. Recently, more and more studies have shown that the manifestations of neurotoxicity caused by bilirubin vary in severity. Severe cases may manifest as kernicterus, while mild cases may not show clinical symptoms, but abnormal manifestations may be found in auxiliary examinations such as brainstem evoked potentials. Most of these subclinical bilirubin neurotoxic manifestations are temporary and reversible, so they are also called temporary subclinical bilirubin neurotoxicity.