It would be tough to treat dog worms effectively without knowing first what type of dog worm your dog has. At any given time, your dog can have any number of worms in his system ranging from the half-inch-long hookworm to the tapeworm. Some can be benign, while others fatal. Learn more about the different types of dog worms, how to distinguish between each, the symptoms your dog will have if he has a worm and the options available for treatment.