Abstract: The significant burden of upper respiratory tract infection in adults and children, coupled with a lack of specific treatment options, invites the use of alternative therapies. Echinacea is an herb widely used for the prevention or treatment of upper respiratory tract infection. This review article examines the mechanism of action, dose, and types of Echinacea used for these purposes. The principal mode of action of Echinacea is through immunostimulation. Most Echinacea studies were done in Germany, but their results are difficult to interpret because of variability of experimental parameters. Types of Echinacea commonly used are Echinacea purpurea, E pallida, and E angustifolia. Both the plant's upper parts and roots are used. For oral administration, tablets, extracts, fresh pressed juice, teas, and tinctures have been used. Though studies show a beneficial effect, clear conclusions and recommendations of Echinacea use cannot be made due to a lack of standard product, variability in dose, and variability in outcome measures. Therefore, well-designed studies with consistent standardized measures are required.
Key Words: alternative therapies, Echinacea, upper respiratory tract infection
A US survey on trends in alternative medicine use found an increase from 34 to 42% between 1993 and 1998, with attendant out-of-pocket medical expenses of approximately $27 billion in 1997. (1) A large portion of alternative medicine users take dietary supplements. A dietary supplement is defined as a vitamin, mineral, amino acid, herb, or other botanical or combination thereof. Under the Dietary Supplements Health and Education Act, dietary supplements are not meant to prevent, mitigate, treat, or cure disease. (2) However, the use of herbal agents has increased in the United States, and national polls report that 32 to 37% of Americans use herbal agents in any given year. (3) The market share of herbal medicine in the United States is more than $4 billion. (4) Some of the most commonly used herbal medicines are products obtained from Echinacea both in Europe and the United States. (5) Americans spend an estimated $300 million per year on preparations of Echinacea. (6) Echinacea sales make up 10% of the total US market in herbal medicine. (7)
Echinacea is primarily used in the treatment or prevention of upper respiratory tract infection (URI), such as the common cold and flu. The cold is one of the most common illnesses in the United States, attributable for 40% of the total time lost from work, and 30% of time lost from education. (8) The expense for cold treatment is estimated at $3.5 billion per year, which includes physician office visits and over-the-counter cold medications. Scientific studies that systematically examine the outcome of Echinacea use at the population level are important because of the widespread use of this popular herb. Questions still remain as to whether we are wasting money on a product that is ineffective or if we are saving money by decreasing the morbidity and mortality resulting from URI, a highly prevalent illness. To answer these questions, we reviewed the literature on the use of Echinacea for URI in...
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