The one thing that I noticed with the post about the baby who vomits is that
the baby does so after being taken off the breast and burped.  Perhaps the mom
can try *not burping* for a nursing or two?  Let the baby come off the breast
like a drunk sailor but leave him be - upright on her shoulder might help.  If
he does have a burp to come up, best to let it come up on its own rather than
whack it out!  I think burping is way overdone in our culture, and is probably
a result of the need for bottlefeeding babies to deal with all that air that
they sucked in with their milk.  Many mothers will naturally rub their little
one's back after a good nursing, baby up on the shoulder (much better to smell
their sweet little heads!) but will do none of that "back banging" that is
often seen with "burping".

My .02, you're welcome to it :-)
Lisa Jones, LLLL in Wellington FL