Why Is My Dog Being Sick Yellow Bile. For example, if your dog is vomiting yellow foam, his stomach is likely empty and the yellow color may be caused by bile or stomach acid in the vomited contents. How to help when your dog is vomiting yellow bile.

One of these is 'bilious vomiting syndrome' or bvs. A veterinarian must diagnose and treat. Bile is a fluid produced in the liver and.