I used to take regular Benadryl as a kid to fight my seasonal allergy symptoms.  I remember playing out in the cottonwood trees for the first part of the day and then coming home when my eyes were swollen shut.  Then I would take some Benedryl and lay down with a washcloth on my eyes.  There went the rest of the day!  I will say I felt fast releif of my symptoms, and I have a sister-in-law who doesn't get sleepy at all when she uses it, but it knocks me out flat for the duration of the day!  I don't use it anymore simply because I couldn't do anything else while taking Benadryl.