In many clinical and laboratory studies, as well as centuries of anecdotal evidence, Echinacea has proven to be one of our most valuable herbs for all types of infection. The root has been shown to increase the secretion of immune-supporting chemicals in the body, while the flowers, leaves, and stem have been shown to increase white cell activity.
Like Arnica, Echinacea can also act as an anti-inflammatory, and Echinacea is strongly topically numbing. All of these actions are systemic, with few specific anatomical affinities, and this combination of effects has led to its widespread use and effectiveness in fighting infections from simple colds, flu, and throat disorders all the way to more serious infections such as venereal disease, blood poisoning, and possibly AIDS, although anyone with a compromised immune system should consult a physician before using any immune stimulant.
Some people have allergic reactions to Echinacea, especially to extracts taken directly in the mouth. Symptoms of that reaction are rash or burning in the mouth, and closing of the throat.
This reaction is rare, and seems to be connected to daisy-family allergies, one of the common causes of hay fever. Often, no symptoms occur if Echinacea extract is taken in another liquid.