Why won't my 4-month-old puppy eat? Is it worms or the food?
If your puppy is not eating at all and this began within the last day or two, I would be very concerned about a serious medical problem - if this is the case, you should get him to a vet right away. Common causes of not eating in puppies would include parvo or intestinal obstruction, but almost any serious illness could cause not eating as a symptom so it would be hard to know the cause without an exam and possibly some blood work or x-rays.
If this problem has been going on for a while and your pup is acting fairly normal otherwise, then yes - it's possible that he could have worms, or he may be a picky eater who would do better with a different diet. You could try deworming him with a dewormer labeled for dogs such as Panacur - you can get this over the counter at many pet stores, just follow the dosing instructions on the label for your puppy's weight. You may also want to try a different brand or flavor of puppy chow, or mix some canned puppy food in with his dry food to see if this helps to tempt his appetite. If this doesn't seem to help, then I would recommend having him seen by a vet to find out if there is some other reason for his poor appetite.
Updated on September 23rd, 2025