The sucking reflex appears in positive infants from 0 to 3 months of age, when something is placed in the infant’s mouth and sucked. It disappears on its own 3-4 months after birth and is gradually replaced by active feeding actions. However, during sleep and on some other occasions, infants still show spontaneous sucking actions 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. So, what are the causes of a positive sucking reflex? A positive sucking reflex in non-childhood is most often seen in pseudobulbar palsy. Pseudobulbar palsy is caused by bilateral upper motor neuron lesions (mainly in the motor cortex and the cortical brainstem tracts emanating from it) that deprive the motor cranial nucleus of the medulla oblongata, the nucleus accumbens, and the motor nucleus of the trigeminal nerve of the pons of the brain of the central paralysis caused by the loss of innervation of the upper motor neurons. In addition to the physiological brainstem reflexes that are active and hyperactive, there are also pathological brainstem reflexes that are mostly primitive reflexes that existed in infancy and were inhibited by the cortex after growth. In general, it is normal for this condition, but if the sucking reflex appears in non-childhood, it should be treated promptly.