'anthelmintic' originates from Greek, specifically the elements 'anti-' and 'helmins' (ὄλμις/ἕλμινς), where 'anti-' meant 'against' and 'helmins' meant 'worm'.

'anthelmintic' entered English via Late Latin/Neo-Latin 'anthelminticus' and medical Latin usages; it then appeared in Modern English with the form 'anthelmintic' (and variant spelling 'anthelminthic').

Initially it literally meant 'against worms' in the original Greek sense, and over time it retained that basic sense, coming to denote specifically drugs or agents that expel or kill parasitic worms.