Psychology Department

Health Psychology Home Page

Papers written by students providing scientific reviews of topics related to health and well being

Search HomeWeight LossAlternative Therapy | Supplements | Eating Disorders | Fitness | Links | Self-Assessment | About this Page |

Is Echinacea the Cure

for the Common Cold?


Emily Ward







what is Echinacea?

            Echinacea has been used for years by the Native Americans to treat various types of injuries and illnesses such as snake bites and cold symptoms; however, was only introduced into European and American cultures starting in the 1920s. (Lindenmuth, 2000).  Echinacea is an herbal remedy made from the purple coneflower and is the most widely accepted herb for stimulating immune response to illness (  There are three different species of Echinacea including E. angustifolia, E. pallida, and E. purpurea.  All three have slightly different phytochemical properties yielding slightly different responses.  Furthermore, bodily response may vary according to the part of the plant that is used in the treatment (Turner, 2005).  Preparations of Echinacea include tablet or liquid extract, either in an alcohol base or tea.  In addition to purple coneflower, Echinacea contains small amounts of iron, iodine, copper, potassium, and vitamins A, C, and E. 

            According to The Herb Research Foundation, the most common uses for Echinacea are in treating or preventing colds, cough, flu, upper respiratory conditions, enlarged lymph glands, sore throat, urinary tract infections, psoriasis, eczema, wounds, skin regeneration, and skin infections ( 


how does it work?      

According to a website dedicated to science and nutrients, Echinacea utilizes alkylamides, polysaccharides, and caffeic acid derivatives to produce the heightened immune system response which is increased production of white blood cells in the body (  Furthermore, research on the biology of Echinacea has shown that the most helpful effect is phagocytosis, or promoting white blood cells and lymphocytes to attack foreign organisms ( According to Evelyn Leigh of The Herb Research Foundation, Echinacea “increases the number and activity of immune system cells,…promotes T-cell activation, stimulates new tissue growth for wound healing, reduces inflammation in arthritis and inflammatory skin conditions,…” and “help prevent bacterial access to healthy cells”(

recommended dosage:          

I found two different recommendations for the amount of Echinacea one should use.  According to an informational website on herbs, for using a liquid extract which is alcohol or glycerine based, one should use .5-5 ml three times per day.  For capsule treatment, they suggest .5-2g three times a day, and for tea they suggest .5-2g per use three times a day (  Conversely, a different website suggests 3-4ml in liquid every two hours the first day of illness, followed by this amount three to four times daily for the length of the illness.  Also, they suggest as a preventative treatment to use 3-4ml liquid or 300mg powdered three times a day solely to stimulate the immune system (


Safety is an important issue when considering an herbal or medicinal treatment to pursue.  One of the main reasons Echinacea is so popular world-wide is because of its efficacy while still remaining quite safe for those who use it.  Echinacea is well tolerated by users and has not shown to produce any harmful side effects ( 

While safe and generally effective, The Herb Research Foundation suggests that Echinacea should not be used for certain chronic and serious health conditions such as tuberculosis, leicosis, connective tissue disorders, or lupus (  Also, while Echinacea is recommended to boost the immune system, reports suggest that Echinacea may lose effectiveness if used for more than 6-8 weeks continuously ( 

how do we know it works?         

I found copious amounts of literature and research on the effectiveness of Echinacea and have found the following to be true: no one is completely sure that is works all the time.  For this paper, I will compare two separate studies that disagree in conclusions on whether or not Echinacea is as effective as it claims.  The first experiment was done by The New England Journal of Medicine and claims that Echinacea produces no significant advantageous effects against rhinovirus infection.  Secondly, an experiment conducted by The Journal of Alternative and Complementary Medicine states that Echinacea is effective in treating the symptoms of cold or flu and significantly shortening the time of infection.

            The first experiment was performed by R. Turner, M.D., R. Bauer, Ph.D., K. Woelkart, T. Hulsey, D.Sc., and J. D. Gangemi, Ph.D.  Their article gives a background about Echinacea, mainly E. angustifolia which is the specific species used in this experiment.  They used 437 volunteers from the University of Virginia area in a double-blind experiment to receive either a prophylaxis or treatment of E. angustifolia root in liquid form or a placebo.  The volunteers were randomly assigned to their specific treatment and made susceptible to rhinovirus type 39 after written informed consent.  The researchers divided the experiment into the prophylaxis stage which was day -7 until the virus was introduced on day 0, and treatment stage which was the day the virus was introduced on day 0 until day 5.  The prophylaxis volunteers took their assigned medications for seven days and then both prophylaxis and treatment volunteers who were asymptomatic (399 in total) were exposed to the rhinovirus type 39 and then stayed in individual hotel rooms for the remainder of the experiment.  For five days, researchers gave scores to the volunteers daily based on symptoms and nasal lavages.  Only volunteers, either prophylaxis or treatment, who actually contracted the rhinovirus infection were evaluated during the experiment.

            The results of the experiment were given in statistical terms depending on the effect Echinacea had before the presentation of the virus to prevent infection or after presentation to expedite the illness or ease the symptoms.  Their results show that Echinacea did not have a significant effect on the volunteers in either group.  In the discussion section, Turner writes that while the components of Echinacea have been studied extensively, the effectiveness of Echinacea is still unverified (Turner, 2005).  He also states that variations in the part of the plant used and the way it is prepared may have a significant effect on how effectively it treats illness.  Furthermore, the discussion states that only a specific form of infection, rhinovirus type 39, was used in the experiment which means that it is possible that Echinacea can provide advantageous effects against different types of infection.  In conclusion, the study can not state definitively whether or not Echinacea is an effective treatment or prophylaxis for a range of illnesses (Turner, 2005).


The second study I will examine was done by G. F. Lindenmuth, Ph.D. and E.B. Lindenmuth, Ph.D in 2000 and examines the effects of herbal Echinacea tea on the duration and severity of illness and symptoms of the common flu.  Lindenmuth used Echinacea Plus which contains E. purpurea and E. angustifolia in liquid form.  In their introduction, the researchers thoroughly examine the history of Echinacea and its different preparations.  They concluded that the liquid form of Echinacea would be more easily absorbed by the body than the pill form, thus deciding to use the herbal tea for their volunteers.  Their volunteers were employees of a nursing home in Pennsylvania who had exhibited symptoms of a cold or flu.  The subjects were randomly assigned in a double-blind study to receive either treatment with the herbal tea or a placebo for five days. 

Their results came back quite differently than the first study.  They gathered their results from questionnaires that the volunteers filled out rating how effective they thought the tea was in three different areas:  the effectiveness in treating their symptoms, the number of days they had the symptoms, and in the number of days it took to notice a change in their symptoms.  The volunteers who had been given treatment with the Echinacea tea reported improvements in all three categories more so than the volunteers treated with the placebo.  While their results were positive, Lindenmuth does suggest that their results may be skewed in some ways.  First of all, 93% of the volunteers were female which suggests that the results cannot be generalized to the entire community.  Furthermore, the ability of the volunteers to withstand infection could be heightened due to working in a medical facility, more so than the general population.  As in the previous study, Lindenmuth concludes his study by stating that the effects of Echinacea need to be studied further to produce more solid results (Lindenmuth, 2000).

so what does this tell us?       

            Through my research on Echinacea I have found that throughout its history Echinacea has been found to be useful to a wide variety of cultures for a range of illnesses and medical calamities.  However, due to the face that no one can decisively prove whether or not Echinacea truly does what it is supposed to do, I am skeptical as to its benefit to the entire population.  I have had personal experience with this herb because I was told to take it just as I was starting to feel sick from a cold.  The first time I used it, about a year ago, I did find that I was not as sick for as long as usual once I started taking the Echinacea.  However, I recently took a course of it about a month ago in the same way I did a year ago and found no evidence whatsoever that it eased the symptoms of my illness or shortened the duration of the illness.  My research for this paper was prompted by this last disappointment with Echinacea and through this research I have found that my experience is parallel to the findings that scientists have discovered.

            Like other drugs, it is possible that different people have different reactions to Echinacea which explains why some experience advantageous effects while others do not.  I believe that Echinacea is a viable option for those hoping to ease the symptoms of a cold judging from its illustrious history; however, one must keep in mind that Echinacea has not been proven to be effective all the time.  Therefore, I would advise people that if a serious malady arose, one may want to consider proven medical treatment instead of Echinacea as an herbal remedy.  




Works Cited

Leigh, E. The Herb Research Foundation: Herb Information Greenpapers. “Echinacea”.


Lindenmuth, G., Lindenmuth, E. (2000). The Efficacy of Echinacea Compound Herbal

            Preparation on the Severity and Duration of Upper Respiratory and Flu

Symtoms: A Randomized, Double-Blind Placebo-Controlled Study. The Journal

Of Alternative and Complementary Medicine.  6, 327-334.

Nutraceutical Science Institute. “Echinacea”.


Turner, R., et al. (2005). An Evaluation of Echinacea angustifolia in Experimental

            Rhinovirus Infections. The New England Journal of Medicine. 353, 341-348.



Psychology Department

The Health Psychology Home Page is produced and maintained by David Schlundt, PhD.

Vanderbilt Homepage | Introduction to Vanderbilt | Admissions | Colleges & Schools | Research Centers | News & Media Information | People at Vanderbilt | Libraries |Vanderbilt Register | Medical Center 

  Return to the Health Psychology Home Page
  Send E-mail comments or questions to Dr. Schlundt