The bait itself (fipronil) is Not going to be life-threatening in a dog, very safe. The main concerned is the actual plastic that it can become obstructed in the gastrointestinal tract or puncture the intestines if there are any sharp edges. Inducing vomiting is not indicated as the plastic can damage the esophagus on the way out. This is what you can do:
1- Do not give things like Pepto Bismol.
2- Do not induce vomiting.
3- Change his diet for the next 2-3 days to rice (75%) and boiled boneless chicken or ground beef (25%). The idea is for the rice to bind the plastic and help pass it out in the feces while protecting the intestinal tract.
4- If at any point during the next few days you see the following symptoms: lethargy, anorexia, vomiting, constipated or diarrhea, etc. follow up immediately with a veterinarian. These are all signs of potential obstruction or perforation of the intestinal tract. In the meantime, observe him and change his diet as above then wean him back into his regular diet.
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