Diagnosis and Treatment of the primary cause of anorexia is crucial in reversing the overall medical problem but treatment of the anorexic condition is the same. If the animal is vomiting, it is imperative that it be stopped. If a dog or cat is vomiting, food and water can not stay down. Drugs of choice include injections of Cerenia® or ondansetron. Once the GI tract is quiet, providing appetite stimulants is appropriate. Oral and or injectable B-complex vitamins, mirtazapine and or cyproheptadine are all used for this purpose. Nutrical® is a high quality energy and vitamin packed gel that is given all the time to provide calories initially to the dog or cat. Mixing that with some Hill's® Prescription A/D works wonders. That can be fed via a syringe or the animal can eat it if able to. That diet is for both dogs and cats. If an animal will not eat, an esophageal or stomach tube may be inserted. One year ago, I had a severely anorexic dog recovering from Autoimmune Hemolytic Anemia and I brought from home chunks of rotisserie chicken from the night before. The dog literally attacked my hands getting to the meat! When, a dog or cat starts to eat on their own, you know they are on their way.