HI
I know you are not doing SCD but this is from PecanBread, an SCD site
"I've consulted with a few people who have gone into massive flares after trying the VSL#3. Also I know lots who have had major problems with bifidum bacteria (especially when on SCD).
Perhaps it is because the SCD clears out the harmful microbes and bifidum takes over, overgrowing into huge numbers. The by-products of bifidum bacteria could be what sends people into flares - especially those who have sensitive guts or those at the beginning of the diet, these people unfortunately have "fertile ground" for bifidum bacteria to overgrow."
I hope this adds something to what you were looking for
David
http://pecanbread.com/new/probiotics1.html