10 Myths About the Common Cold and Flu

Fact or Myth? Echinacea or zinc can help prevent or shorten the length of a cold.

Answer: Probably a Myth

Both zinc and echinacea have had a number of studies done on them, and neither has been shown conclusively to help battle colds.

"There have been a number of studies of echinacea. Some have purported to show some modest benefit. However, I think the weight of the evidence is that echinacea has no benefit, either on incidence of illness or severity of illness," said Turner.

He said the results for zinc have been similarly ambiguous.

"There are a number of studies that have been done looking at the effect of zinc, primarily on the severity of illness and duration of illness," said Turner. "Those studies have been split really between studies that show fairly dramatic effects and then an equal number of studies at least that show very little or no effect."

While the evidence is not entirely conclusive, Turner said, he wouldn't be rushing out to get his hands on some zinc.

"I think it's a little hard to know exactly what the final answer is on zinc right now, although, in my opinion, I suspect that it doesn't have a whole lot of impact on common cold illness," he said.