Cassie, chocolate toxicity and symptoms are very dose dependent. Symptoms can range from gastrointestinal symptoms to life threatening seizures
or cardiac arrhythmias. Milk chocolate is among the least toxic
of the different types of chocolate. I am finding the king size bar is 2.8 oz, I don't believe this will be fatal for your dog. But, to be on the safe side I would try to induce vomiting with peroxide. This is what you can do:
1- Move quickly and induce vomiting. To induce vomiting give 1/2 tablespoon of hydrogen peroxide orally.
2- Allow him to walk for a minute and move his belly to mix stomach
content with peroxide. If he does not vomit within 5-10 minutes, repeat it again. Can give a total of 3 times 5-10 minutes apart.
3- If he does not vomit after 3rd dose or you do not see the chocolate in the vomit observe him for the next 24 hours. If he becomes hyperactive, muscle
tremors, changes in respiration, etc. have him checked immediately by ER veterinarian, these are symptoms that could progress to life threatening seizures or cardiac arrhythmias. If no symptoms after 24 hours (especially the first 12 hours), he will be fine.
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