The 40-day-old child’s nose does not work in the following cases: 1, the child has just recently had a nose that is not ventilated, pay attention to whether there is a cough, spitting bubbles or coughing phlegm, pay attention to whether there is a cold or fever around, and whether the child has choked on milk. If all these problems are present, you need to take your child to the doctor in time, the doctor will listen to your child, and if necessary, perform a chest X-ray to clarify whether there is pneumonia or bronchitis. 2, if your child has intermittent nasal obstruction since birth, pay attention to whether there are congenital problems in the nasal tract, and go to the ENT department for a clear diagnosis. 3, if your child is prone to nasal obstruction in a certain environment, but a change of environment will relieve it, pay attention to whether there are allergies. It will be relieved, pay attention to whether there are allergic factors causing thickening of nasal mucosa or increased nasal secretion, and it is best to take the child to a specialist for a clear diagnosis.