Infant lacrimal duct blockage is mostly due to congenital factors. Infants have a membrane in the lower nasal canal that should automatically atrophy at birth, and the nasolacrimal duct will be open. Some infants do not have this membrane atrophied at birth, so it causes blockage of the lacrimal duct and the infant exhibits tear overflow and even causes pus flow, leading to neonatal dacryocystitis. For the blockage of infant lacrimal duct, it can be observed at 1-3 months of life, and if there is discharge at this stage, antibiotic eye drops can be ordered appropriately to suppress inflammation, and after 3 months most children can clear it by themselves. If it does not clear on its own and shows overflowing tears or pus, tear duct irrigation should be performed. If the lacrimal duct does not improve after 3 times of lacrimal flushing, it is recommended to carry out lacrimal duct probing, generally the lacrimal duct probing can be successful once, and after probing and flushing 3-4 times, the lacrimal duct blockage can be basically cured.