My Dog Is Vomiting Blood, Has Bloody Diarrhea, Won’t Eat or Drink, Is Weak, Shakes Its Head, and Breathes Heavily

Based on your description, the dog’s vomiting blood, bloody diarrhea, refusal to eat or drink, and heavy breathing may be caused by poisoning or an infectious disease such as canine parvovirus infection. After a dog is infected with parvovirus, it first vomits, then vomits blood and passes bloody stool with a foul fishy smell.

If these symptoms appear, take the dog to a veterinary hospital for diagnosis and treatment promptly. Note that vomiting and bloody stool are fairly serious symptoms, so timely treatment is important.