Why does my dog vomit on walks?

Review your feeding schedule: sometimes, when dogs get an upset stomach, simply keeping the dog from ingesting food and water for a few hours after they have vomited will resolve the symptoms. However, often times, vomiting yellow bile is a sign that a dog hasn't eaten in a long time, or there has been too long a period of time between meals. If the bile is yellow and hy, you should try feeding small meals throughout the day to see if that solves the problem.