Hello and thank you for your question!
My initial thought was that Splenda (sucralose) is no problem for dogs, but I thought I had better double check. I went on my professional website and looked up Splenda as far as any possible toxic effects. Another vet had written in the same question, that they had a client asking if splenda or other artificial sweeteners are toxic. This was the toxicologist's response:
Your client may have heard about xylitol being toxic to dogs (which it can be); it has incorrectly been indentified in some reports as an artificial sweetener (it is not; it is a naturally occuring sugar alcohol).
Saccharin has been shown to cause bladder tumors in male rats at high doses but that is a result of the pecular physiology of male rats. Dog fed a diet that contained up to 7% saccharin for 13 weeks had no abnormalities.
With sucralose, dogs fed 900 mg/kg/day for a year had no abnormalities so it has very little acute toxicity.
Not that there is any reason to feed either to dogs anyway but they are unlikely to cause acute toxicity if ingested.
Eric Dunayer, MS, VMD, DABT
VIN consultant: Toxicology
ASPCA Animal Poison Control Center
So great news, there is no shown toxicity with sucralose (Splenda) so your dog should be just fine. I suspect the diarrhea is due to the XXXXX XXXXXie dough and should improve with time.
Thank you! Dr. Marcia