Newborns with blue on both sides of the nose may be a normal physiological phenomenon, but also may be pathological phenomena such as congenital heart disease, congenital vascular developmental malformation, lung disease, etc.. 1. Normal physiological phenomenon: may be due to the thin subcutaneous fat, capillary rich and caused by a normal phenomenon, as the child grows up this phenomenon will gradually disappear. 2. Pathological phenomenon: (1) congenital heart disease: newborns with congenital heart disease are prone to hypoxia, blue on both sides of the nose, accompanied by blue lips and poor peripheral circulation. (2) Congenital vascular malformation: newborns with tender skin and poor vascular development may cause blue on both sides of the nose. (3) Lung disease: newborns suffering from pneumonia and lung infection diseases often show bad performance such as blue on both sides of the nose and blue lips. There are more reasons that lead to blue on both sides of the nose of newborns, and it is recommended to bring newborns to professional pediatric hospitals in a timely manner.