The eruption of teeth in five-month-old babies is a normal physiological phenomenon and generally does not require special clinical treatment. Under physiological circumstances, normal babies begin to erupt their milk teeth within four to ten months after birth, and only babies who have not yet erupted their milk teeth after thirteen months after birth are considered to have delayed eruption of milk teeth, so the baby’s teething at five months of age belongs to the normal physiological state, and does not generally require clinical treatment. The common clinical causes of delayed eruption include hypothyroidism, calcium deficiency and poor ectodermal growth. If the baby has not erupted milk teeth after thirteen months, it is recommended to go to the stomatology department or the child health department, and standardize the treatment under the guidance of the doctor.