Why is my Bichon vomiting yellow fluid?

A Bichon vomiting yellow fluid may be from food irritation, a food change, eating a foreign object, or an infectious disease. In a young Bichon, suspect diet, gut inflammation, or intestinal parasites.

Sudden food changes, unclean food, or eating too fast can trigger it; young Bichons also easily get tapeworms or roundworms, which worsen it. In older dogs, beyond those causes, tumors or liver/organ disease may be the reason — treat the underlying cause.