The Pusher by Steppenwolf
Comin in to Los Angeles by Arlo Guthrie
Lucy in the Sky with Diamonds made me want to take LSD as a youngster, whether Lennon admits it was about acid or not
Morning glory by Oasis are we counting that one?
QOTSA - Feel good hit of the summer (C-C-C-C-C-COCAINE!!)
Slightly different angle but Neil Young and The Needle and the Damage done
I also think White Lines by Grandmaster Flash is an absolutely superb song which was way ahead of it's time, with some very good advice in it, don't do it!
White Rabbit by Jefferson Airplane
Eminem - Purple Pills
I think there's a couple of McCartney ones as well but off the top of my head I can only think of Let Me Roll it and that ain't one of my favourites really