"I really thought the raw garlic was going to work," says Christopher Gardner of Stanford University's Prevention Research Center, the study's lead author.

The study is in today's issue of the Archives of Internal Medicine. It divided 192 adults with moderately high cholesterol into four groups for treatment with either raw garlic, powdered garlic supplement, aged garlic extract supplement or a placebo.

The garlic-consuming volunteers took the equivalent of one medium-size clove six days a week for six months. Their blood was drawn every month to check their cholesterol levels.

Previous studies testing various garlic supplements have shown mixed results, but there was good evidence in test-tube and animal studies that garlic could lower "bad," or LDL, cholesterol, Gardner says.

Crushed garlic contains allicin, which has been shown to inhibit cholesterol synthesis in the test tube, so "there's biological plausibility for it to work," Gardner says. "The question is: If you give it to a human to consume, will it get to the right place at the right time and result in your blood cholesterol going down?"

Thirty-thousand sandwiches made with garlic-laced condiments and twice that many pills later, the answer came back: It won't. There were no significant effects on LDL cholesterol concentrations or in triglyceride levels, another indicator of heart-disease risk.

Garlic is one of the top five most popular single-category herbs (as opposed to those sold in combinations), says Grant Ferrier, editor in chief of the Nutrition Business Journal. Total garlic supplement sales for 2006 were about $160 million, he says.

Bob Borris of the Council for Responsible Nutrition, a dietary supplement industry group, countered that garlic is meant as an aid in maintaining good cholesterol levels in an already healthy population. Garlic can keep people from developing high cholesterol, he says.

The study was well designed and innovative in its use of not only commercial garlic supplements but also raw, fresh garlic, says Richard Nahin of the National Center for Complementary and Alternative Medicine, which financed it. And the results weren't necessarily surprising, he says. "If you look at the literature going back to 1995, most of the studies (on garlic) have ended up being negative," Nahin says.

But the news is not all bad, Gardner says. The pungent bulbs are so tasty that they might steer people in the direction of more healthful foods.

"Eating hummus on a whole-wheat pita or an Asian veggie stir-fry will probably lower your cholesterol, and you'll enjoy them more with garlic," he says. "But it's not going to turn garlic french fries into cholesterol-lowering fries."