Friend, when a dog is vomiting undigested food it is called "regurgitation" as the food has not been digested. There are many possible causes. It will be difficult for me to determine the exact underlying cause without a hands on examination. But, common possible causes are: Esophagus disorders (megaesophagus, strictures, parasites), gastritis, tumors or even part of a systemic disease. To determine the exact underlying cause she will need a hands on examination with family veterinarian, xrays and blood work as initial screening test. In the meantime this is what you can do:
1- Do not give things like Pepto Bismol or imodium. Start her on Zantac (ranitidine) 75 mg 1/4 tablet every 12 hours. You can buy Zantac over the counter in any pharmacy (chemist).
2- No food or water for 3-4 hours. Need to give her gastrointestinal tract time to rest.
3- After 3-4 hours offer a small amount of water. Wait half hour, if no vomiting, offer small amount of rice (50%) and boiled boneless chicken or ground beef (50%) 4-6 times a day.
Note: Raise her eating bowl on to a small stool to force her to raise her head when she eats.
4- Follow up with your family veterinarian for a hands on examination.
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