'galactagogue' originates from Greek, specifically the word 'galaktagōgos', where 'galakt-' (from 'gala') meant 'milk' and 'agōgos' meant 'leading' or 'bringing forth'.

'galaktagōgos' passed into New/Medieval Latin as 'galactagogus' and was later borrowed into English as 'galactagogue'.

Initially it meant 'that which leads or brings forth milk', and over time it came to mean specifically 'an agent that stimulates milk production'.