'antidotarium' originates from Medieval Latin, specifically the word 'antidotarium', ultimately derived from Greek 'antidoton' (ἀντίδοτον), where 'anti-' meant 'against' and the root from 'didonai/δόδωμι' related to 'give' (i.e., 'that which is given against' a poison).

'antidotarium' changed from Greek 'antidoton' into Late/Medieval Latin forms such as 'antidotum' and 'antidotarium' and was later used in learned English as a borrowing referring to a collection or book of antidotes.

Initially it referred to 'a substance or thing given against poison' (an antidote), but over time it came to denote specifically 'a book or collection of such remedies' (a pharmacopeia of antidotes).