Echinacea was used by many Native American populations throughout the country. This widespread use was adopted by the Eclectic physicians in the U.S. and its use was documented in medical texts until 1947. A German pharmaceutical manufacturer imported E. purpurea to Germany in the 1930s.
This herb is popular both In Europe and in the United States. As a result of many clinical trials that were done in the 1990's Echinacea sales account for approximately 10% of the dietary supplement market. Many are still being conducted today.
Although controversial, scientific studies conclude that Vitamin C does not prevent the onset of cold symptoms, it may reduce duration. However, in a subset of studies in people living in extreme climates or under extraordinary conditions, including soldiers in sub-arctic exercises, skiers, and marathon runners, vitamin C significantly reduced the risk of developing colds by approximately 50%.
Zinc appears to be an essential trace element for the immune system, and further research is needed to confirm the few studies that have been done.
Copper is added to balance the zinc, which if taken without copper, may cause a copper defienciency.

As an herbal supplement, take two capsules twice daily with food. It is best to take supplements containing zinc with food; otherwise slight nausea may be experienced.
Nutritional supplements containing echinacea should be used with caution in individuals with autoimmune diseases. Individuals diagnosed with Wilson's Disease should not take copper supplements. Not recommended for long-term use without periodic breaks. Not recommended for use during pregnancy or while nursing, until further research verifies no contraindications. Keep out of reach of children. Discontinue if unusual symptoms occur. Do not exceed recommended dose unless under the guidance of a health care professional.
Individuals sensitive to sesquiterpene lactone-containing plants in the Daisy family should use all Echinacea supplements with caution.