Medically reviewed by Daniel Combs, MD Benadryl (diphenhydramine) is an over-the-counter (OTC) antihistamine commonly used to ...

An incorrect dose of Benadryl could be extremely harmful, which is why you need to make sure you administer a dose based on ...

Always consult your veterinarian before giving Benadryl to your dog. The correct dosage of diphenhydramine for dogs depends on their weight. A small dog will need much less than a big dog to ...