Nasolacrimal duct probing does not induce bacteremia in routine CNLDO cases unless there is an associated acute dacryocystitis. Preoperative antibiotic prophylaxis is perhaps not needed for systemically healthy CNLDO patients without an acute dacryocystitis. However, with regards to infantile acute dacryocystitis, further evidence is needed to formulate guidelines on additional preoperative antibiotic prophylaxis other than the routine treatment of infection.