If you are purchasing the liquid form of Benadryl, be sure to read the ingredients since some types contain the artificial sweetener xylitol, which is toxic to dogs. The normal dose of Benadryl ...
Diphenhydramine counteracts histamine and thus decreases symptoms. It takes about 20 minutes for symptoms to improve after you take a dose. Learn more about Benadryl and dosage. EpiPen ...