'vermifugal' originates from Latin, specifically from the Neo-Latin/Latin term 'vermifugus', where 'vermis' meant 'worm' and 'fugare' (from 'fugus') meant 'to drive away' or 'to flee'.

'vermifugus' (Latin) passed into Neo-Latin/early modern medical usage as 'vermifugal' and was adopted into English with the same form and meaning.

Initially it meant 'driving away worms' in a literal sense, and this has remained largely consistent; modern usage denotes a substance or property that expels parasitic worms (an anthelmintic).