galactagogue
Concise Oxford English Dictionary © 2008 Oxford University Press:
galactagogue /gəˈlaktəgɒg/
▶noun Medicine a food or drug that promotes the flow of a mother's milk.
– origin C19: from Gk gala, galakt- ‘milk’ + agōgos ‘leading’.
'galactagogue' also found in these Oxford entries:

