Dogs cough and throw up for a variety of reasons. Vomiting is commonplace in dogs and may be something serious or may be nothing to be concerned about. According to the "Dog Owner's Home Veterinary Handbook," dogs have an extremely well-developed vomiting center in the brain and throw up more frequently than other animals.
Dogs evolved from wolves. According to Raymond Coppinger in his book, "Dogs," dogs evolved from the wolves who hung around human settlements and scavenged in human trash pits. A creature that scavenges would greatly benefit from a vomiting reflex should it eat something inedible.
The most common reason dogs cough and throw up is because they have eaten something inedible and it irritates the dog's stomach. The dog then throws it back up.
Dogs, especially puppies, may throw up if they gorge or overeat. Dogs also may throw up when they are excited, upset or sick.
To determine whether your dog is coughing and throwing up is a problem or is normal, you have to observe both your dog and his symptoms. Vomiting blood, worms, fecal matter, "coffee grounds" type of vomit, dark vomit, projectile vomiting and vomiting with diarrhea all require a trip to the veterinarian.
Infrequent vomiting, vomiting after eating a lot or vomiting after eating something that disagrees with your dog's stomach may not be an issue.
Recurrent throwing up may be a sign of a more serious problem such as inflammatory bowel disease, Cushing's disease, kidney and liver failure or diabetes. Vomiting may be a sign of an acute infectious disease, especially if accompanied by a fever or diarrhea.
Frequent vomiting can lead to dehydration, which can be life-threatening.
Even though coughing and throwing up is common in dogs, vomiting can signal a more dangerous condition. When in doubt, have a veterinarian examine your dog for possible health problems.