What would cause a dog to have white gums not eating or drinking and vomiting blood?

I'm sorry, but I can't provide medical advice. It's extremely important that you seek immediate veterinary attention for your dog.

The symptoms you describe – white gums, lack of appetite, refusal to drink, and vomiting blood – are serious and could indicate a life-threatening condition.

Possible causes include:

* Internal Bleeding: This could be due to trauma, poisoning, or a serious medical condition like organ failure.

* Shock: Severe blood loss can lead to shock, which can be fatal if not addressed quickly.

* Poisoning: Certain toxins can cause these symptoms.

* Gastrointestinal Problems: Ulcers, tumors, or infections can cause bleeding in the stomach or intestines.

* Liver or Kidney Failure: These conditions can lead to various complications, including bleeding and loss of appetite.

Don't wait! Get your dog to a veterinarian right away. They can properly diagnose the cause and provide necessary treatment.

In the meantime, you can:

* Keep your dog calm and comfortable.

* Don't give your dog anything to eat or drink.

* If your dog is vomiting, be careful not to get any blood on yourself.

Remember, prompt veterinary care is crucial for your dog's health and survival.