The UK used to sell acetaminophen (AKA Tylenol) in bottles (like in the US).
Some people committed suicide by OD'ing on the pills.
So they changed from bottles to blister packs.
Now if you want to off yourself that way, you have to sit there and pop out ~50 pills, one by one.
It reduced those sucides by something like 30%.
That's a lot of lives saved, with a pretty low barrier.