Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
Especially since one other dog has this digestive disturbance, they probably ingested something odd that is causing this. The treatment for a minor digestive issue is as follows:
Fast your guy for 12-24 hrs to allow the digestive tract to calm down and heal.
Give him Pepcid AC or Famotidine at 0.5 mg per pound every 8 hrs. That can be purchased over the counter at the pharmacy.
Give only small amounts of water during the fast or ice cubes
After the fast, feed rice and boiled chicken (2/1)
If the vomiting has resolved, then wean him back onto regular food. If the vomiting persists especially during the fast, take your guy to your vet for an exam and lab work to determine the cause for this. This is extremely important since this can cause dehydration or other more serious concerns such as infection, metabolic issue or intestinal obstruction.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
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