Vomiting on an Empty Stomach

Question
My 3 year old terrier, vomited yellow, foamy fluid early this morning.  I offered him light food (rice and vegetables) to eat and water.  He refused.  Although his behavior this morning was a little sluggish, this afternoon he is behaving normally, but still refusing his food (although he wanted some of my lunch).  What causes him to vomit on an empty stomach?

Answer
Any time a dog vomits up yellow foamy fluid it usually means that the dogs pancreas and bile ducts are inflamed. Acute pancreatitis is from a dog eating something new or fatty, like a little piece of bacon in the morning or ham.

Other liver problems will also cause a dog to vomit bile. The most common cause however is the above.

The best thing to do is fast your dog for 24 hours then feed him rice and baby food chicken until he is back up to par. Cut out all treats and people food- for good.

You can give small carrots for treats or larger ones are like a bone to them.
If your dog is still vomiting or off his food by tomorrow then you need to call the vet. Untreated pancreatitis can be fatal.
I hope you didn't give him any of your lunch.

Dogs that get pancreatitis once are prone to get it again and it will strike without warning but always after eating something they are not used to eating.