America’s on-again, off-again romance with echinacea could be on again.

The popular herbal supplement, made from the purple coneflower, might reduce the chances of catching a cold by 58 percent, according to the latest in a long line of confusing and contradictory studies.

Better yet, echinacea might reduce the length of a cold by an average of 1.4 days – a substantial savings, because colds cause 40 percent of lost U.S. work time, the authors of a recent study say.

The study, conducted by scientists from the University of Connecticut, is to be published online Monday in The Lancet Infectious Diseases, a British medical journal. Echinacea is an herb with a long-standing medicinal reputation among Americans, who spend an estimated $2 billion a year on nonprescription cough and cold remedies.

Other studies have shown the opposite. In 2000, scientists reported that echinacea could help treat colds but not prevent them.