Morning Chelle,
I got a list of toxics from my vet awhile back, and the begonia's were listed.
Also checked the ASPCA site, and they list it as well.
http://www.aspca.org/pet-care/...
I've got dogs, and they don't mess with my plants, now that they are grown. Thank goodness! But, it's funny,(not haha) just like kids, everything goes right into the mouth!