Benadryl is a trade name for diphenhydramine, produced in the U.S. by Warner-Lambert. It is sold over the counter in pink tablets or pink and white capsules of 25mg each. An adult dose is 50mg.

Diphenhydramine is an antihistamine used to quell allergic reactions. It also causes drowsiness, and is used by some as a sleep aid. My personal experience with this has involved substantial morning-after incoherence, so careful experimentation is recommended. My friend Lisa reports that her mother used to give this drug to her and her younger siblings before long plane trips. This might actually be illegal in some states, so it's a good thing I've used a pseudonym.