Echinacea angustifolia, ... Wagenius, who led the research, tracked a 40-hectare plot, or nearly 100 acres, of prairie land in Minnesota for 21 years as part of the Echinacea Project.

According to the Minnesota Department of Natural Resources, Echinacea angustifolia is the only coneflower native to Minnesota. You may see it blooming this time of year in ditches and roadsides.

An evaluation of Echinacea angustifolia in experimental rhinovirus infections. N Engl J Med 2005 Jul 28; 353:341-8. Sampson W. Studying herbal remedies. N Engl J Med 2005 Jul 28; 353:337-9.

For the new study, researchers recruited 399 young adults. Some received drops of Echinacea angustifolia extract and others got placebos. After a week, all volunteers received nasal sprays ...