I am sorry that Gizmo is not feeling well. When we see blood with diarrhea this is a sign of inflammation in the large intestines. The vomiting is a consequence of whatever is causing the inflammation. This can be caused by many different medical conditions. It will be difficult for me to determine the exact underlying cause without a hands-on examination and some testing, I am sorry. But, common causes are dietary indiscretion, ingestion of a foreign body, infections, or even part of a systemic disease, etc. to name a few causes. To determine the exact underlying cause Gizmo will need a hands-on examination by a veterinarian, blood work, 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. 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 on this diet for several days then wean into regular diet.
4- Follow up with your family veterinarian for a hands on examination. If cost is a concern I would look into your local ASPCA or Shelter where they often offer veterinary services at a lower cost.
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