'lactagogue' originates from New Latin (Neo-Latin), specifically the word 'lactagogus', where 'lact-' (from Latin 'lac, lactis') meant 'milk' and '-agogus' (from Greek 'agogos') meant 'leading' or 'bringing'.

'lactagogue' changed from Greek 'galaktagogos' (literally 'milk-bringing') into a Latinized form 'lactagogus' and eventually became the modern English word 'lactagogue'.

Initially it meant 'that which leads or brings milk', but over time it evolved into the current meaning 'a substance that promotes milk production'.