The World Health Organization (I wish I had the speidfic reference)
specifically says that breastfed babies should continue to be breastfed
during gastroenteritis (vomitting and Diarhea) Even the Harriet Lane
Handbook (the sort of bible pediatric interns walk around with) says  that
they should.  The whole business of stopping dairy products for shor term
diarhea is not well proven either.