Six-month-old babies with red lines at the junction of the penis and scrotum may be normal physiological structures or may be due to eczema and other causes. If a six-month-old baby has a red line at the penis-scrotum junction, if it is not accompanied by localized rash, it is a physiological phenomenon, which may be the middle line of the scrotum or the prepuce tie, and it may be red due to the tenderness of the baby’s skin. If the localized skin is accompanied by itching, the baby will scratch involuntarily, at this time there will be a rash, then it may be caused by eczema. When a baby develops abnormal changes in the skin at the penis and scrotum, it is recommended to seek medical attention and intervene under the supervision of a doctor to promote relief of the discomfort. It is important to wipe after sweating to keep the baby’s skin dry and hygienic.