[MargaretR]

Epsom salts
Back in the days when doctors weren't just drug dispensers, I was directed by my doc to take massive doses of Epsom salts in order to stop production of breast milk. The effect of producing liquid diarrheoa for a day caused my breast milk to dry up,(and enabled my return to work)

There was no adverse effect from this temporary self induced dehydration.
No doubt women are prescribed expensive drugs nowadays to get the same effect.