Echinacea: Is it effective for the common cold?

Maybe, but not by much. Some research suggests that echinacea supplements may shorten the duration of a cold and may slightly reduce symptom severity. But these results were too minor to be considered important.

Some studies have found echinacea to be helpful while other studies have found no benefit in treating colds. Part of the problem is that echinacea products can contain different concentrations of the herb. And the echinacea extracts used in these products can come from the flowers, stems or roots of three echinacea plant species. This makes it difficult to compare study results.

Echinacea generally doesn't cause problems for most people. But some people taking the herb have reported side effects such as an upset stomach or diarrhea. Echinacea also has the potential to interact with other medications you might be taking, so talk with your health care provider before using echinacea supplements.