The contents of the pillow core may be buckwheat husk, millet, However, the contents of the pillow core should be replaced once every three months. Babies can sweat and drool, which can seep into the pillow core. Long-term causes moldy food and other articles in the pillow core. Mould will enter the air through the fiber gap of the pillow core, which is easy to be inhaled into the respiratory tract by children, causing cough, runny nose, even excessive wheezing and other allergic phenomena.