Anyone give their baby probiotics?

CA2006

Pedi recommended trying probiotics for DD's tummy troubles. DD will only sleep on us on her tummy or side. When like this, she will sleep 4-6 hours at a time. On her back (propped or not), she will wake after 1 hour grunting, crying and then poop. She still poops several time/day (at least 6-8) and it tends to be mucousy. So, anyone else have success with probiotics?