The highest vet bill for a dog can vary greatly depending on the situation. The most expensive treatments are related to cancer or serious injuries. A single surgery can cost anywhere from $2,000 to $15,000 and may require additional treatments such as chemotherapy or radiation therapy. Some rare diseases can also be very costly, with bills sometimes reaching upwards of $30,000. Regardless of your vet bill, it's important to remember that it's always worth it to provide the best care possible for your furry friend! Pet insurance is also good, so you're covered in an emergency.