Blocked nose and poor breathing in babies is due to the narrow nasal cavity of babies. If stimulated, it will cause congestion, edema or increased mucus secretion from the glands of the nasal mucosa, which will lead to blocked nose or poor breathing. The irritation of the nasal mucosa is generally divided into two major factors: infectious and non-infectious. Infectious factors, as the name implies, are cold, flu, bacterial or viral irritation, which cause congestion and edema in the nasal mucosa and increased secretion of mucus glands, resulting in blockage of the nose. In addition, non-infectious factors are allergies, which can cause congestion and edema of the nasal mucosa after the baby is exposed to allergic substances, and can also lead to poor breathing. The specific problem depends on whether there are combined respiratory symptoms.