A dog's loss of appetite can be the sign of a serious problem. Dogs that won't eat should be seen by the vet to address the underlying problem. Often medication can help soothe the stomach irritated by illness and improve his appetite. Taking the time to feed the dog slowly and continually can help get the dog to eat.
A dog that won't eat is an indication of several conditions, all of which can potentially be serious. If your dog won't eat for more than a day or has other symptoms present, like vomiting or diarrhea, you should take her to the vet as soon as possible. Your vet can perform some diagnostic tests to determine why she isn't eating and advise an appropriate treatment plan to get her back on track.
Some conditions like cancer or pancreatitis can be very painful, making the dog lose his appetite. In cases similar to this it can be a good idea to administer medications that will stimulate the appetite or protect the stomach lining. When a dog quits eating and is under the stress of illness, the stomach will produce excess stomach acid. With no food to digest, the excess acid erodes the stomach wall causing the dog to feel nauseous. Medications like carafate or omeprazole can help control this acid and eliminate nausea. With the nausea under control, the addition of an appetite stimulant can help get the dog to eat. If these medications do not result in an increased appetite, inform your vet as more drastic measures may be needed.
Sick dogs often need particular care to start eating again. Start with a highly palatable food. Baby food is often a good choice as it is tasty but not hard to eat. Make sure the baby food you feed does not contain onions as they can be toxic to dogs. Begin by force feeding the dog small amounts every hour. If the dog won't eat the baby food, smear it on his lips so that he has to lick it off. For a dog that hasn't eaten in a while, a tablespoon can be plenty of food initially. Continue these small force feedings every hour. Typically, when the dog starts to get some food in his belly it is enough to kick start his appetite. Increase feeding amounts gradually.
For dogs with a chronic illness that don't want to eat, try cooking food for them. Mix cooked ground turkey or beef with rice and veggies. Home-cooked food is often more palatable than regular dog food. Whatever the dog wants to eat is what you should feed her. You can try warming her meals slightly or adding some baby food to make it easier to chew. Offering small meals every couple hours can also help her to not feel overly full and nauseous.