Scott Lukas, professor of psychiatry at McLean, a psychiatric hospital affiliated with Harvard Medical School, says these results inspired his team to test on humans. The study was conducted on 14 men and women, average age 24 years, in a “laboratory” apartment where each person was allowed to drink as many as six beers. After determining how much each person drinks normally, half were given a capsule of kudzu or an inactive pill, or placebo.

“Those who took kudzu drank significantly less than those on placebo,” says Lukas. “[The kudzu group] downed an average of one or two beers while the placebo group finished three or four. Alcohol consumption was almost cut in half.”

Those on kudzu also drank more slowly. “They needed more gulps to finish each beer,” Lukas continues. “That tells us they are responding to cues from their brains telling them they don’t need to drink so much.”

Kudzu also causes few side effects. “We gave our subjects a low dose for one week,” Lukas explains. “Then we gave them blood and urine tests and physical exams. No changes were found. If we raised the dose and gave it for a longer period, alcohol consumption might be decreased even more.”

Although no one knows exactly why kudzu increases sobriety, researchers theorize that the herb speeds alcohol’s effect on the head.