No, Benadryl will not effectively euthanize your dog unless done properly. There are not many great at-home over-the-counter medications that will euthanize your dog.
If you are looking for an effective way to euthanize your dog, call your vet. They can assist you with euthanizing your dog.
If you give your dog Benadryl, there are some side effects that you need to know about that you may see from high dosages of Benadryl.
Benadryl is an effective anti-histamine for dogs. If your dog is having an allergic reaction to something or has allergies, Benadryl is a great choice.
It can take 6 to 12 hours before your dog starts getting relief from taking Benadryl. This is why it is not an effective medication to use to euthanize your dog.