Both Andrea Simmons and Chanita have a great point that needed to be brought
up about Valerian potentially making breastmilk smell different.

Jim Duke likens the smell of valerian as like dirty gym socks. I can certainly
see the potential for putting off babies if they "inherently" don't like it.
If anyone has seen babies put off by maternal use of specific herbs, please
post.  Currently there's very few info sources that provide this level of
detail about herbs and breastfeeding.

 Julie Mannella theorizes that (I would say at least some but not all)
galactogogues work by altering the milk smell/flavour in a pleasant way.
Apparently they like garlic, for a change at least.  From recent posts on
vanilla, would say they like that too.  But did the mom have to keep using
vanilla or taper off?

Fennel, anise, dill, etc. all contain trans-anethole - a chemical constituent
that Jim Duke lists as a sweetener.  In his older book ( Handbook of Medicinal
Herbs) "anethole" is listed as a galactogogue (cis and trans forms were not
distinguished in the references, but cis-anethole is bitter) .  Could it be
that fennel and relatives flavour the milk so that babies are eager to nurse
more, thus assisting in increasing milk supply? Or, alternatively, has anyone
noted a lack of galactogogue effect with a mother pumping milk for her baby?

Sheila Humphrey  BSc(Botany)  RN  IBCLC