Dogs who eat fly poison will generally have a poisoning reaction within a few hours. If the toxicity of the fly poison is relatively small, the dog may not have a reaction, so it depends on the actual situation of the dog. After discovering that the dog has eaten fly poison, you should immediately induce vomiting in the dog. If it cannot induce vomiting, you need to send the dog to a pet hospital immediately to find a professional doctor for induced vomiting treatment.
