She adopted the brown puppy named Tammy in June and renamed it Coco.
Four months later, the pup allegedly turned nasty, attacking her, her children and a neighbour's children.
Clinic receptionist Alison McElvee then sought help from a professional dog trainer but to no avail.
She was even unsuccessful in re-homing her, so as a last resort, Ms McElvee had the dog put down.
That was when trouble started - for her and the vet who carried out the euthanasia.
A post on the Facebook wall of Save Our Street Dogs (SOSD) making claims about Tammy's condition and subsequent death went viral.
It received some 660 comments and was shared by almost 1,000 people.
Animal lovers and netizens were up in arms, calling both Ms McElvee and the vet from The Animal Clinic names.
Tammy the puppy was rescued in April together with its four siblings.
It was the first among the litter to find a home.