Q. He has been vomiting several times daily for about 6 weeks. The food is undigested. Switched from dry to tuna. Always hungry. Retches .
A. The most important thing to do is get him in to your vet for an exam and labwork, especially if this is a new problem and he is showing other symptoms, such as weight loss, excessive thirst, rough coat, etc. These could be signs of hyperthyroidism or diabetes. If he seems fine in every other way, he may be regurgitating, rather than vomiting. If the food is coming back up very soon after eating, virtually unchanged, he may be eating faster than the stomach can take it in. It fills the esophagus and then triggers the gag reflex, causing him to bring back everything he just ate. Try putting big river rocks or glass nuggets in his bowl of food, so that he is forced to slow down and eat around them.