What are these for?

I'm at the vitamin store and go to check out with my bottle of fenugreek.  The clerk tells me it's buy one get one half off.  I tell him I'm going to go and get another bottle of the same thing.

Clerk:  What is this stuff good for anyway?
Me:  Breastmilk production.
Clerk: [totally embarassed] I wish I hadn't asked....