When a baby has a cold or fever, the nasal mucosa is damaged and the relative resistance is lower than usual, so the nasal mucosa becomes congested and swollen, and the blood flow is faster than usual. The superficial blood vessels and capillaries under the mucous membrane rupture and bleed, causing nosebleeds more easily than usual. The most common cause of bleeding in babies is that they do not master the correct way to blow their nose. Because the nose, ears and eyes are connected, it is often said that the seven orifices are connected. Some babies like to blow their nose as hard as they can, so the pressure in the nasal cavity will suddenly increase and the blood vessels will easily rupture and bleed. Some babies also like to pick their nose with their fingers when their nose is uncomfortable, which can easily break the nasal mucosa and cause nasal bleeding. This time can even lead to inflammation extending from the mucous membrane of the nose to the sinuses, to the ears, and even to the eyes, causing corresponding sinusitis, catarrhal otitis media, and even conjunctivitis. Therefore, we should pay attention to the correct way to blow the nose, do not pick the nose casually by ourselves, and also pay attention to replenish water to prevent the nasal mucosa from being too dry and causing the rupture of capillaries to bleed. You can apply erythromycin ointment to the nasal cavity and follow up at any time.