Will Benadryl make my dog sleep?
Photo Credit: Courtesy of 3DStockPhoto (dog image)
One of the side effects of Benadryl is drowsiness, which helps to calm anxious dogs. The Merck Veterinary Manual states that diphenhydramine may relieve symptoms of mild-to-moderate anxiety in pets associated with travel. It also may help relieve motion sickness during car rides and plane rides.