What Are The Basics of Benadryl for dogs? What do I need to know? Just what is Benadryl, anyway? Benadryl is a brand name for Diphenhydramine. This is a product that treats many symptoms of allergies, insomnia, anxiety,  in addition to other issues as well. What are the basics of Benadryl that you need to know? Technically, Benadryl is an antihistamine that blocks the H-1 receptors on smooth muscle and blood vessels. It is one of the very few over-the-counter drugs that veterinarians prescribe for use at home. Stick with me through the medical jargon necessary in the first few … Continue reading What Are The Basics of Benadryl for Dogs?