I had bought Yogis once for my ferrets that were Cranberry flavoured.
And of course, out comes red stool.  I didn't connect it at the time
because I was so concerned about the babies being sick that I had my
husband drive to the vet on his lunch break, plastic baggy in tow, to
have the vet take a look.  I don't know about the dye in twizzlers
but the Yogis sure colour things (including the carpet in front of the
litter box!).
 
Heather
[Posted in FML issue 4089]