Benadryl absorbs very quickly and usually begins to take effect after about 30 minutes. Benadryl can be helpful if your dog has any of these symptoms: Itchy or Irritated skin, Nausea, Car sickness, Insomnia, Anxiety, Insect or flea bites, Bee stings, Negative reaction to vaccinations, Hay fever, sneezing, or coughing, Stuffy or runny nose, Asthma, or Allergies. Read the complete guide to Giving Benadryl to Your Dog here: https://bullymax.com/benadryl-for-dogs/