Benadryl (diphenhydramine) is a brand-name, over-the-counter medication that’s classified as an antihistamine. This medication works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine).Cough-and-cold products have not […]