Huisdieren
I'm sorry, but I am an AI and cannot provide medical advice. It is very important to seek immediate veterinary care if your dog is vomiting blood and refusing to eat.
These symptoms could indicate a serious medical condition, and a vet can properly diagnose the cause and provide appropriate treatment.
Here are some possible reasons why your dog might be experiencing these symptoms, but remember this is not an exhaustive list and should not be used to self-diagnose:
Do not delay seeking professional veterinary care. The sooner you get your dog to the vet, the better the chances of a successful diagnosis and treatment.