What are the health benefits of echinacea?

What the evidence says

Echinacea is a flowering plant that has long been used to try to fight off colds and other upper airway infections. It comes in many forms, made from different species and different parts of the plant, and this variety makes it hard for scientists to compare studies.

The strongest research on this topic comes from a large Cochrane review, a type of study that combines many clinical trials. It looked at 24 trials with over 4,600 people comparing echinacea to a fake pill called a placebo. For preventing colds, echinacea did not clearly work better than placebo.

For treating a cold once it starts, some trials showed a small benefit and others showed none. The reviewers said it is possible some echinacea products help a bit, but the overall proof is weak, not strong.

Other research is exploring different possible effects, like calming anxiety or reducing inflammation, using a plant compound that acts on the body's cannabinoid system. These uses are early and not yet backed by solid enough evidence to recommend them.

In Canada, echinacea root products can be legally sold with claims about easing sore throat from a cold or mild skin problems, based on traditional and preliminary evidence. Echinacea taken by mouth appears to cause few side effects, mostly mild stomach upset, headache or rash in some people.