What kind of gum was it? Most sugar-free gums contain a potentially dangerous ingredient called Xylitol. If you don't have the wrapper, you should look up the ingredients of the particular brand. Your safest bet is giving your vet a call.
Not it was not sugar-free, it was the Big Chew gum that is supposed to look like tobacco chew, but it was the gum. My little cousin was playing with him and it fell out of her mouth and before i could get it the dog did and i had no time to get it out of his mouth before it was gone.