Dogs vomiting green liquid may be caused by gastroenteritis, gastrointestinal ulcers or improper diet. The green liquid is bile. If they eat dirty things by mistake, it may also cause the dog to vomit bile. If the symptoms are not serious, the dog needs to be deprived of food and water and observed for a day or two. If the situation is serious, it needs to be sent to the hospital for examination and treatment in time. It is best not to feed your dog random food, especially bones and raw meat.