All dogs will vomit or spit up from time to time.  If a dog is just the nervous type or starts gagging, they might throw up their food or a type of phlegm.  Sometimes a dog will eat something it shouldn't have and vomit that up.

However, vomiting blood is never considered to be normal and should ALWAYS be investigated by your veterinarian.  Among the potential causes for this would be certain poisons or something the dog swallowed that has damaged the esophagus and/or stomach.

Don't let this linger!

Helpful Buckeye