If mother's milk is in question as a source for the blody emesis, milk can be
tested with a hemocult kit (I think they are available OTC).  It takes only a
few seconds to do the test. The baby who is vomiting blood and has dark
stools should have the stools tested for occult (hidden) blood. I often test
milk when the physicians insist that the blood is coming from mother: [mostly
to prove them wrong]. Milk is so light in color that the amount of blood
needed for bloody emesis should be visible to the naked eye. Also inspect the
mother's nipples for small papercut-like tears. An interductal papiloma may
also cause blood in the milk. In some cases the blood was not evident with
pumping but could only be seen with manual expression.
I had a baby with profuse vomiting of large amounts of bright red blood. The
doc insisted it was from mom, he who went so far as to type the blood the
baby vomited  (dah.. it was the baby's)  The little guy had a severe  Mallory
Weisse tear and needed transfusions.
Motto: never downplay the presense of blood.
Re: mom with ulcer:  I have heard the latest on ulcers is that most are
bacterial in nature and resolve with antibiotic tx. Any input from the MD's?
Marie Davis