What happens if someone swallowed an oral anesthetic (anbesol)?

Probably nothing. It isn't unusual to swallow or taste a little after you apply it to your gums for a canker sore or toothache. But be careful--an overdose of the medication (benzocaine) in anbesol can lead to a dangerous condition called methemoglobinemia, which deprives your system of oxygen. Never use adult strength anbesol for children or babies. Follow the directions carefully and use only a little at a time.