I am sorry your dog is vomiting. In response to your question, the green color vomit is bile, if you are now seeing pink this could be blood. The big question is: Why is he vomiting? Vomiting 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 gastritis, dietary indiscretion, ingestion of a foreign body, infections, etc. to name a few causes. In this case, if he is vomiting so much I would strongly recommend seeking for a veterinarian for a hands-on examination and some testing to try to determine the exact underlying cause. In addition, he may need supportive care of IV fluids, anti-emetics, etc. In the meantime, in any case of vomiting the first thing to do is give the stomach time to rest. This is what you can do:
1- Do not give things like Pepto Bismol or Imodium. Start him on Pepcid AC (famotidine) 20mg 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 on this diet for several days then wean into regular diet.
4- Follow up with a veterinarian for a hands on examination and supportive care as soon as you can.
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