If the diarrhea is the only symptom and your dog is otherwise acting normal and has no vomiting, follow these instructions on Home Care for the Dog with Diarrhea. If your dog is lethargic, weak or begins vomiting, it is safest to call your veterinarian so they can examine him to help determine the underlying cause and provide additional treatment recommendations.
If your dog is vomiting, you can follow these instructions: Home Care for the Dog with Vomiting. If your dog is lethargic or weak, it is safest to call your veterinarian so they can examine him to help determine the underlying cause and importantly provide additional treatment recommendations which may include fluid therapy and/or injectable medications (since he is vomiting and may be unable to keep oral medications down).
If your dog is having both vomiting and having diarrhea, you can follow these instructions: Home Care for the Dog with Vomiting and Diarrhea. These instructions include specific recommendations on what to do at home in this circumstance. However, if your dog is acting lethargic, weak or showing any other abnormal signs, the safest thing to do is to take him to your veterinarian. They may want to do additional testing to determine the underlying cause such as blood work and/or radiographs or treat with fluids, injectable medications, bland foods, and/or oral medication for when the vomiting has subsided.
We hope this article helps you understand the best way to start a new food for your dog by mixing a small amount of the new food in with the original food and do this over several days.