Nightmares in children can usually be caused by daytime overexcitement, psychosomatic factors, calcium deficiency, and illness. 1. Over-excitement during the daytime: if children play too excitedly, exercise too much or watch scary books or movies during the daytime, the cerebral cortex will still be in a state of relative excitement at night, which will lead to the phenomenon of nightmares after going to sleep. 2. Spiritual and psychological factors: if parents often suppress their children, discipline them too strictly, or parents often quarrel, it is easy to make the children nervous, anxious and fearful, which will make the children’s central nervous system in a state of high tension for a long time, thus producing the phenomenon of nightmares. 3. Calcium deficiency: if children lack calcium in their bodies, it is easy for them to suffer from sleeplessness, dreams, nightmares and even muscle spasms. It is recommended to check your child’s blood calcium and vitamin D levels. 4. Disease factors: for example, if a child suffers from rhinitis, pharyngitis and other diseases, such diseases will make the child suffer from nasal congestion, poor respiratory tract, etc., which will easily cause the child to suffer from lack of oxygen in the brain during the process of sleeping, which will also cause nightmares, and it is recommended to treat the original disease actively. All in all, children who have nightmares occasionally usually do not need special treatment. If the child has nightmares for a long period of time, it is recommended to consult a doctor in time.