The sucking reflex is one of the reflexes that mammals and human infants are born with and is one of the unconditioned reflexes of newborns. When a newborn’s lips and mouth are touched with a nipple or a finger, there is a corresponding sucking and wriggling of the lips and tongue. It disappears on its own 3-4 months after birth and is gradually replaced by active feeding movements. However, during sleep and on some other occasions, the infant still shows spontaneous sucking movements for a period of time. If the sucking reflex disappears or is significantly weakened during the neonatal period, it suggests an intracerebral lesion; if it is hyperactive, it is a sign of hunger; its presence after 1 year of age suggests cortical dysfunction. This is one of the reflexes that mammals and human infants are born with. This reflex is formed at birth and the sucking action of the lips can be observed when the fetus is stimulated at the 18th week. The sucking reflex is evident after birth and continues for 4 months after which it is gradually replaced by an active sucking action. However, during sleep and in some other situations, infants still show spontaneous sucking for a period of time. The sucking reflex and the milk-seeking reflex are complementary reflexes and must be followed by a sucking action in order to really achieve the effect of drinking milk and supplementing nutrition. Otherwise, the bottle or nipple is placed in the baby’s mouth, but the baby is unable to suck. This shows that if the infant is unable to suck to get food, there may be a problem with neurological development and the infant’s ability to absorb nutrients in the right way and in the right amount. The sucking reflex is an important indicator of normal brain development in newborns. If these two most primitive reflexes are not present at birth, the infant will have difficulty eating and maintaining life, so it may be suspected that the infant has brain damage such as hypoxia, ischemia, or brain lesions. However, a diagnosis can only be made after a detailed examination and evaluation, not because the infant does not show a certain reflex response, it definitely means that the infant is suffering from a certain disease or developmental abnormality. Nowadays, medical science has used the sucking reflex of comatose patients to turn “waste” into “treasure” and successfully place a gastric tube. Method: The gastric tube is placed through the nose, and when the head end reaches the opening of the esophagus, the patient touches the corner of the mouth with a finger, and then the patient sucks and swallows, and then the gastric tube is placed in place slowly and gently in rhythm with his sucking and swallowing. This method is simple and easy to use, and solves the problem that comatose patients often cannot follow the instructions to do swallowing movements to cooperate with the nurse for intubation, so that medical staff often find it difficult to place the gastric tube.