Friend, vomiting and loose stool 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. But, common causes are: A simple gastritis, dietary indiscretion, pancreatitis, ingestion of a foreign body, infections, etc. to name a few causes. The shaking could be a sign of discomfort.
In this case, to determine the exact underlying cause Jax will need a hands on examination by family veterianarian, xrays and blood work as initial screening test. In the meantime, in any case of vomiting or loose stool the first thing to do is give the gastrointestinal tract 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) 10mg 1/2 tablet every 12 hours or Zantac (raniditine) 75mg 1/2 tablet every 12 hours. You can buy Pepcid AC or Zantac 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 small amount of rice (50%) and boiled boneless chicken or ground beef (50%) 4-6 times a day.
4- Follow up with your family veterinarian for a hands on examination.
Note: If you are seeing muscle spasms I would have him checked by ER veterinarian, this could be a sign of electrolyte disturbances.
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