In short, if you are wondering if your dog can eat marshmallows, the answer is yes, marshmallows wont harm your dog, but becuase they are high in sugar, they are very unhealthy.
More Information About Marshmallows For Dogs
As long as you are not giving your dog a large quantity of marshmallows, marshmallows are not harmful to dogs. They are not toxic, however because they are high in sugar, if a dog eats a large amount they can get sick. If your dog eats too many marshmallows they can begin to vomit and they can get diarrhea. Depending on the size of your dog, if they ate a lot of marshmallows, and have severe vomiting or diarrhea, you should bring them to a vet.