Nasal congestion that occurs at night but is normal during the day in children is considered to be caused by adenoid hypertrophy or rhinitis. Parents need to determine the cause of the onset according to the accompanying symptoms and take the child to the ENT department of the hospital for a comprehensive examination. Common causes and treatment methods are selected: 1. Adenoid hypertrophy: When adenoid hypertrophy occurs, the gland will block the nostrils and cause the eustachian tube to be compressed, leading to breathing difficulties, accompanied by symptoms such as runny nose. The symptoms are more pronounced at night when sleeping because of the lying position, and in severe cases, apnea and other adverse consequences can occur. Adenoid hypertrophy is usually treated by surgical removal; 2. Rhinitis: the baby’s exposure to dust mites, dust or other items that cause allergies can trigger allergic rhinitis and nasal congestion symptoms. Parents need to determine whether they will be exposed to certain items that cause allergic rhinitis in their children at night. They can go to the hospital for allergen testing to rank which items cause allergies and take antihistamines, such as loratadine, under the guidance of a doctor, or, in the case of infectious rhinitis, may need to apply anti-infective drugs, such as penicillin. In either case, during the treatment period, parents should pay attention to regularly washing the child’s pillow, quilt cover and other items to keep the child’s sleeping environment clean and dim, and to ensure air circulation. A humidifier can be placed in the house to keep the indoor air moist. In addition, observe whether there are any nasal stools in the child’s nasal cavity. If there are more nasal stools, they will easily block the nostrils and cause nasal congestion, and need to be removed in time.