'antitoxine' originates from Modern French/Latin formation, specifically the French word 'antitoxine', where 'anti-' meant 'against' and 'toxine' (from Greek 'toxikon') meant 'poison'.

'antitoxine' was formed in the late 19th century alongside developments in serum therapy; it appeared in French and Latin medical literature and was borrowed into English, where the spelling 'antitoxin' became the standard.

Initially it meant 'a substance that counteracts a toxin'; this core meaning has been retained into modern usage (now usually spelled 'antitoxin').