'antidotal' originates from English, specifically the word 'antidote' with the adjectival suffix '-al', where 'antidote' came into English via Latin 'antidotum' from Greek 'antidoton', with Greek 'anti-' meaning 'against' and the root from 'didōnai' (to give).

'antidotal' changed from the noun 'antidote' (borrowed into Latin as 'antidotum' from Greek 'antidoton') and later formed as a modern English adjective by adding the suffix '-al'.

Initially the root meant 'something given against (a poison)', and over time the adjective 'antidotal' came to mean 'relating to or acting as an antidote' and more generally 'counteracting harmful effects'.