Well last night a person crushed up 100mg of diphenhydramine
into a nice powder, and packed it into his cone to smoke. Here's what he found..
It was very hard to burn, it seemed to want to melt, not cherry. The smoke had a HORRIBLE taste, and did a number on his lungs. He pulled the whole bowl in one hit and held it in for a few seconds, after exhaling he got a slight buzz in his head but no real effects. Later in the night, he started getting a headache and eventually just went to bed.
So, from A persons experiment, he concludes that smoking diph has no real effects.