Dogs that are unconscious cannot be induced to vomit. First off, they cannot swallow the peroxide and it gets in their lungs resulting in the potentially fatal, aspiration pneumonia. If by chance, it does get to their stomach.
What happens if a dog doesn't throw up hydrogen peroxide?
If the H2O2 works its magic, your dog should vomit within two to five minutes of receiving the first dose. If he doesn't vomit within five minutes, it's okay to re-dose. Then stop.
How long after a dog has hydrogen peroxide will they vomit?
This method usually results in your dog vomiting within 10 to 15 minutes, if it going to be effective. If possible, giving your dog a small meal prior to administering the hydrogen peroxide may help in the treatments effectiveness. If it does not work, it can be repeated once more.
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