Boo, a six-month-old black crossbreed puppy, gave herself and her owner a fright when the life-like object got lodged in her intestines.
Shelly Bryson, 33, from Dundee, called animal charity PDSA for help.
"My daughter Reese, 7, accidentally dropped a bag of dog biscuits and they got mixed up with the fake dog poo that had been left on the floor," she said.
"For some reason Boo decided to eat it and swallowed it down in one. I got straight on the phone to PDSA as she had been sick and was refusing to eat and they told me to bring her in immediately."
The joke item moved into Boo's intestines and caused a potentially fatal blockage, said vet Stephan Hunt at the PDSA PetAid hospital in Dundee, Angus.
"We gave Boo intravenous fluids to keep her hydrated and carried out emergency surgery to remove the object from her stomach."
Dogs often swallow things they should not, behaviour known as pica, Mr Hunt said.
"Dogs use their mouth to explore objects as well as to eat them. Sometimes the two functions get confused and a dog will eat an object by mistake, even though it had only meant to investigate it."
He stressed the importance of stopping dogs from eating non-food items and highlighted signs for owners to look out for.
"Symptoms suggesting blocked intestines include vomiting, abdominal pain, restlessness, dehydration and loss of appetite. If your pet shows any of these signs, you should speak to your vet immediately."
Ms Bryson, praised the work of staff at PDSA.
"The family had been worried sick about Boo. I thought I was going to lose her. I'm so grateful to PDSA for saving her life," she said.
"We can all laugh about it now but at the time everyone was very worried."