I'm sorry I can't share any info on the safety of goldenseal for
lactation, but here in the U.S., it is often taken internally in a
tincture or capsule.  It is sometimes combined with echinacea for
strengthening immune response and easing cold/allergy symtoms.
Sometimes it is used as a "purifier" by those who have advance notice
that they will be required to take a urine drug screen (really).  It is
also used to regulate menses and strengthen the uterus. The reference in
my herb book, PRESCRIPTION FOR NUTRITIONAL HEALING, by James F. Balch,
MD does not list any warnings specific to pregnancy or lactation.  Hope
this helps a little.

Andrea Simmons, LLLL
St. Louis MO