Kipling was known to smoke opium for inspiration but these days I think most writers would agree that there are wiser-and safer choices out there!
My own personal favorite would be Twizzlers. Technically they are a non-addicting substance, which is a plus over Mr. Kipling's choice. But, like chocolate, I'd have a hard time going cold turkey. Plus, they're fat free-hey, you can't beat that! True...there's some sugar content that adds a few calories, but honestly, how many of these puppies would I have to eat before my normal, semi-workout routine wouldn't take care of the aftermath?
And of course they use up a lot of nervous energy that would otherwise make me want to do wacky things like clean toilets or do laundry, rather than stare at my uncompromising computer screen which takes all my inspiration and creativity while only giving me spam and errors in return. Oh, and hopefully a good book now and then!