There's an off licence near shepards bush tube station.
That specialises in absinthe. Any kind you could possibly imagine from 55% up to 90. Three whole walls, plus a window full of bottles and a small magazine rack. Brilliant place.

Eastern European absinthe is nasty chemically stuff that is generally over 70% and is little more than horridly strong booze. Typically drunk by necking it after stirring a melted spoon of sugar into it.

French absinthe is a different animal. The good stuff is generally around the 60% mark and it rarely goes above 70. It contains the more funky ingredients and should be prepared by mixing it with water that is dripped into it over a sugar cube. It should then be sipped, and generally treated more like pastis than a shot.

All of the hallucinogenic reputation comes from the fact that wormwood in sufficient quantities can cause them, but it mostly comes as an attempt to explain why 100 or so years ago, highly strung Parisian bohemian types tended to go slightly loopy after years of abusing the stuff.
(Woodlouse say it with flowers. Send her a Triffid, Tue 19 Feb 2013, 21:31, Reply)