SAN FRANCISCO -- Green fairy, opalescent muse, bottled madness, the essence of life: absinthe has answered to many names over the centuries, feeding inspiration and insanity in equal measures to artists from Baudelaire to Degas before facing a ban that lasted nearly a century.

Now the emerald witch is stepping out of the shadows.

Since the federal government approved the sale of absinthe in March, two brands of the high-proof liquor, Lucid and Kubler, have been introduced to the U.S. market. Both made according to original recipes, they are fueling a revival among the inquisitive and quenching the thirst of cultish devotees.

Drawn out by the dissolution of national barriers in the European Union, absinthe also is newly legal in its birthplace, Switzerland, and in France, whose fin-de-siecle painters and writers enshrined its allure in masterpieces that survived the drink's prohibition on the eve of the first World War, and ensured its reputation.

''I'd read about it in Henry Miller and Anais Nin, and I was curious,'' Stephanie Palmer, who works in software sales, said while sipping Kubler absinthe on the night of its sponsored debut in a San Francisco bar. ''It has this mystique -- all the stories about wormwood.''

Wormwood, an herb that grows wild on the slopes of Val-de-Travers, in the Swiss Alps, is absinthe's key ingredient, and counterbalances the mouth-numbing sweetness of the dominant flavor, anise. A relative of tarragon and mugwort, it imbues the drink with bitter undertones and, reputedly, the drinker with a clarity of vision that made it both beloved and banned.

''After the first glass you see things as you wish they were,'' Oscar Wilde once said of absinthe. ''After the second, you see things as they are not. Finally you see things as they really are, and that is the most horrible thing in the world.''

A chemical present in wormwood, thujone, has long been credited with keeping the drinker lucid even as he succumbs to the pleasant lull of alcohol. Recent studies have shown that wormwood excites the nervous system, said Barnaby Conrad III, author of ''Absinthe: History in a Bottle.''

''It's a little like stepping on the gas and the brakes at the same time,'' Conrad said.

As he spoke, he prepared a glass of absinthe in the traditional way: placing a flat, slotted spoon across a tulip-shaped glass, balancing a sugar cube on top, then opening a thin-spouted spigot on a tabletop fountain and allowing the trickle of water to melt the sugar into the clear absinthe below.

On other tables, patrons tried it for themselves, enjoying the ritual involved in preparing the drink using the old-fashioned glass fountains supported by elegant metal pedestals.

When water was added, the mixture turned a milky, alabaster hue -- a process known as the louche, a French word meaning ''shady,'' which could be applied to the drink's opaque appearance or to the allegedly dubious virtues of those who consumed it.