Yes. It makes you sleepy. As a chronic insomniac I would take it to get sleepy. Except for prescription sleeping pills, which the doctors don't like to let you have on a nightly basis and due to their high cost, the Benedryl worked the best and lasted 6 hours if I was lucky, but then again, I'm a hard-core insomniac and once was up for two weeks before I started taking medications.
For me, the Benadryl could sometimes take up to three hours to kick in, but if I took it on a semi-empty stomach and followed it with a few walnuts or something that gives your stomach something to work on, it would sometimes kick in, in a matter of minutes.
Benedryl has also been used in nursing homes for patients that couldn't fall asleep w/the sleep inducing ingredient @ 50 mg. The ones at the store come in doses of 25 mg. each and that is really all I ever took. Only on a few occasions, would I take two but found it wasn't necessary most of the time.