Do Dogs Cough Up Hairballs. It, at times, can be a little tough to watch. If the hairball becomes too large to pass through the intestines, or cannot be coughed up, it can cause a blockage in the digestive system and begin to ferment.

Coughing or vomiting up hairballs is the most obvious sign that your dog has a problem with them. Why is my dog coughing up hairballs? Keep a lookout for their first hairball efforts, as young kittens not yet accustomed to coughing up hairballs can become lethargic and stop eating for a day or 2.