Hope, when we see bloody stool this is a sign of inflammation in the large intestines. The vomiting is a consequence of the inflammation. It is possible this could be related to the ingestion of a foreign body especially if he is a dog that tends to eat anything. Other possible causes are intestinal parasites, infections, or even part of a systemic disease, etc. to name a few causes.
In this case, I would recommend a hands-on examination with your veterinarian and x-rays as an initial screening test. In the meantime, this is what you can do:
1- Do not give things like Pepto Bismol or Imodium. Start him on Pepcid AC (famotidine) 10mg 1/4 tablet every 12 hours for the next 2-3 days. You can buy Pepcid AC over the counter in any pharmacy.
2- No food or water for 6-8 hours. Need to give his gastrointestinal tract time to rest.
3- After 6-8 hours offer a small amount of water. Wait half hour, if no vomiting, offer a small amount of rice (50%) and boiled boneless chicken or ground beef (50%) 4-6 times a day. Keep him on this diet for several days then wean him into his regular diet.
4- Follow up with your family veterinarian for a hands on examination. If cost is a concerned I would look into your local ASPCA or Shelter where they often offer veterinary services at a lower cost.
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