It's friday night. happy hour at a popular bar in the Mission; liberal shots with chasers are on sale for half price. By 5:30 the regulars are lined up at the door, jonesing for their end-of-the-day fix. "l'm really going for it tonight," enthuses one grinning young man. "l'm get ring two triples!"

He's slugging down a potent potion that can't get you drunk, although arguably it can give you a high --an energy high, that is. It's wheat grass juice, the green liquid that many proponents swear has innumerable health benefits, such as preventing tooth decay, improving digestion, curing dandruff, and detoxifying blood. Fanatics stick it in virtually any human orifice--mouth, nose, vagina, anus--and even put the pulp on their skin to treat bruises.

As if they were in some kind of natural-health-channel version of Cheers, the grass-happy denizens here at Wheat Grass Growers Farm and Depot know one another's names. There s the woman who buys the grass to treat her boyfriend's prostate cancer. There's the artist who uses her daily shot to rid her body of toxic chemicals that she may have absorbed while working with oil paints. They banter with one another and the farmer and proprietor, Eva Moen.

"This AIDS is really kicking my ass. I really need the energy!" exclaims one agitated customer as she waits for her shot with her daughter, who grumbles about how bad the stuff tastes. "Anything that's good for you tastes kind of nasty," says another patron, who downs her two-ounce shot from a paper cup in one gulp.

in a slow moment, David the bartender speculates that he might be getting so many good tips today because of the sweater he's wearing-it's bright green, just like the pungent mash that he's slowly producing from the juicer.

The exterior walls of this cheery red barn, near the -corner of 15th Street and Guerrero, are covered with pamphlets proselytizing the wonders of wheat grass and its life-giving chlorophyll. Inside, slogans above the bar offer chipper mantras like "purifies air and water" and "protects against radiation!" One wall holds a makeshift shrine to Ann Wigmore, the modern-day prophet of wheat grass. A quote from Wigmore's book, "Be' Your Own Doctor, reveals that she was fulfilling the teachings of ancient prognosticators: "120 centuries ago, on the continent of Atlantis, it was predicted that the real health-giving properties of WHEAT GRASS would be learned by some far distant generation, when men would be given the key to save a tottering civilization from extinction." As Moen sees it, she's quite literally on a mission from God: "God gave me a vision, I was floating in space, and I saw the world covered with short green grass." She woke up at midnight, not sure of the dream's significance -astroturf? -- until she encountered wheat grass a few days later at a health food store. To commemorate this sacred beginning, a picture of Moen, arms outstretched, as if in a night flight to enlightenment, is tacked to the ceiling.

Like a mythic hero, Moen tried to resist her calling--why me, God? --but eventually came around and accepted her mission. "God wouldn't leave me alone about this wheat grass," she shrugs.

Moen attests that the grass coupled with a chaser called Rejuvalac --a yummy, flavored drink containing enzymes--cured her of severe alcoholism and weight problems. "Of course, no one believes me. But it's the truth."

Since she started her business in the '80s, when her chief customers were local pet-food stores, "wheat grass has proven itself," she says. She isn't bothered that many medical doctors and even natural health gurus like Dr. Andrew Well reject all claims about its powers. She answers to her God, not the American Medical Association. And it's the fervor of zealots like Moen that makes you understand why the many health-conscious types in the mainstream --joggers in the Marina and stroller-pushing moms in Noe Valley--now think it's good to drink the juice.

Moen's ultimate goal: wheat grass on every breakfast table, like orange juice. Just inside the door there's an artist's conception of the wheat grass franchise that she aims to inspire. It looks like a natural foods McDonald's, complete with outdoor picnic tables and parking spaces.

And in the crowded bar during happy hour, it seems devilish or at least mean to ask whether the elixir really works. These serious juicers find their salvation in their own chlorophyll-enhanced world, where the grass really is always greener. ·