"I think we need a lot more research before we start taking echinacea off the shelves," he said.

Some people take echinacea at the first sign of a cold, hoping they will be able to keep the cold from developing.

Do not take echinacea without first talking to your doctor if you are pregnant or could become pregnant.

Do not take echinacea without first talking to your doctor if you are breast-feeding a baby.

Many people take echinacea in the hopes that it will boost immunity.

Given the lack of evidence, children and pregnant or breastfeeding women should not take echinacea unless their doctors have approved it.

If you have allergies, be sure to check with your healthcare provider before taking echinacea.

Participants who took echinacea shortened their colds by an average of 1.4 days.

Still others took echinacea or a placebo at the time they were infected.

He takes it and echinacea three times a day at the first sign of a cold.