Can be used as a recreational drug but not recommended. Its found in benedryl and several other OTC medications. It will make you have hallucinations of things that aren't really there.
I bought a box of 36 capsule of generic benadryl with the intension to use it to get high and boy was it a trip. I took them all at one time (each tablet has 25mg of diphenhydramine in it so i got a 900mg dose of it) and about 45 minutes later the walls were wavy like the gentle rolling on a pond in a breeze and had a lizard around me all night(which really wasn't there says my friends) that was cool. The only thing I didnt like about it was the slight nausea and extreme dry mouth and throat, other than that I find it a cheap version of Acid (LSD). If your under 250 lbs. I wouldn't recommend taking as high of a dose as I did or even using it at all to get high. If you decide to disregard my warning atleast have some wits about you and don't over do it cause it could KILL you one thing I didnt find out until I got curious and looked it up on the internet. Otherwise have fun with it and be smart on how much you take!