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 |



Amber Dixon

Date: 11/16/2005




The common cold is one of the most prevalent human illnesses.  Colds are caused by viruses.  There is no cure for the common cold, but people use many treatments to prevent and treat troubling symptoms.  Echinacea is a herb many claim is helpful in treating colds.  It is a popular known herb used around the world.  It is the best known herb for increasing the immune system’s resistance to infection.  Echinacea is growing in popularity because of media attention to its reputation of boosting the immune system.  However, it is not certain if Echinacea is actually beneficial in treating colds and other infections.




What is Echinacea?


Echinacea is a flower native to North America mostly found in the Midwest United States.  The Echinacea plant grows in the United States from the Midwest to the prairies of Pennsylvania.  It is a plant that grows 1-2 feet tall and looks spiny.  Echinacea is a common name for three species of daisy plants called: Echinacea angustifolia, Echinacea pallida, and Echinacea purpurea.  The plants are commonly known as narrow-leaved purple coneflower, pale purple coneflower, and purple coneflower respectively.  Echinacea angustifolia has other common names such as hedgehog coneflower, black sampson, sampson root, and rudbeckia (  Echinacea is used as an herbal medication.  The medication is obtained from the roots, stems, and leaves of Echinacea purpurea.  Dried rhisomes and roots are used from Echinacea angustifolia and Echinacea pallida.  The rhizomes and roots are used most often in preparations of medicine.  In some medicinal preparations the whole Echinacea plant is used.  The Echinacea plant has been over harvested and is now being considered for endangered species status.


History of Echinacea               


Echinacea has been used for hundreds of years as a stimulant, anti-viral, and bacterial aid.  Native Americans, mostly Plains Indians used Echinacea for medicinal purposes.  The Native Americans used Echinacea as a herbal remedy for treating and preventing colds, flu, and infections.  It was thought by the Native Americans that the herb possessed antibacterial, antiviral, and antifungal properties.  Some examples of Echinacea's uses by Plains Indians is it was used as an antiseptic, analgesic, treat poisonous insect and snakebites, toothaches, sore throat, wounds, and infectious diseases such as smallpox, mumps, and measles.  Echinacea was also used by the Cheyenne, Choctaw, Dakota, Sioux, and many more tribes.  When settlers came to the New World they adopted Echinacea uses and it has been used in America ever since.  Echinacea gained more popularity in the United States in the 1800's.  Many doctors widely prescribed Echinacea as natural remedy for infections (   Also, Echinacea became known in Europe around 1895.  In Europe, Echinacea preparations are used mostly to stimulate the immune system and help prevent common cold infections affecting nose and throat (  Echinacea products have the greatest popularity in Germany, where they are approved for treatment of respiratory and urinary infections and for external treatment of wounds.


Echinacea Uses           


One of the primary uses of Echinacea is to treat and prevent colds, coughs, flu, and many other upper respiratory infections.  Topical Echinacea preparations are used in the treatment of wounds, burns, eczema, psoriasis, herpes infections, and skin conditions.  It may also increase resistance to candida and other infections (


-Upper respiratory conditions                                       

-Sore Throat

-Urinary Tract Infections

-Help resist herpes and candida

-Wounds and skin infections (External use)

-Inflammatory skin conditions (External use)      



How Echinacea Works


Echinacea has a reputation of boosting the immune system in treating colds and fighting infections.  It increases the amount of white blood cells in the body, which causes a boost in the immune system and enables the body to fight infections.  Basically, Echinacea increases the nonspecific activity of the immune system.  It stimulates the overall activity of certain immune cells responsible for fighting infections and makes the body's own immune cells more efficient in attacking bacteria, viruses, and abnormal.  Echinacea stimulates phagocytosis, T-cell formation, and inhibits hyaluronidase enzyme secreted by bacteria.  Echinacea basically just helps the body maintain its line of defense against unwanted invaders (


- Increases number and activity of immune system cells

- Promotes T-cell activation

- Stimulates tissue growth for healing of wounds

- Reduces inflammation

- Prevents bacterial access to cells by inhibiting hyaluronidase






Echinacea is taken in many different forms and dosages.  It is available in dried root or herb, capsules, creams, gels, tablets, powder, and liquid extracts (  Dosage recommendations are based on the type of Echinacea preparation.  For example, 500 mg per day of one Echinacea extract may be effective (based on presence of active compounds), whereas 1000 mg of another extract may be ineffective (if the active constituents are too low) (  The normal dosage recommendation for Echinacea is 250-500mg a day of a concentrated extract.  A tea made from Echinacea is good for the acute stages of an infection.  The liquid extract is good for the flu and an urinary tract infection.  Capsules can be used for treating cold, flu, urinary tract, and kidney infections.  Most specialists recommend Echinacea be taken for four weeks and then not taken for a week instead of continuous treatment.  As far as cold and flu symptoms go, specialists recommend that Echinacea be taken as soon as symptoms appear and continued 2-4 times per day for 1-2 weeks.


-Liquid Extracts: Dosage amount ranges from one to five drops per use three times a day.


-Capsules: 1/2 - 2 g per use three times a day.


-Tea: 1/2 - 2g per use three times a day.




Internet Information


On the internet, Echinacea is marketed as a dietary supplement to promote a healthy immune system.  Echinacea is currently one of the top five best-selling herbs in the country that generates more than $300 million in sales every year.  It is a favorite among herbal and alternative medicine experts.  Echinacea is often sold as combination of the three popular Echinacea plants.  It is sold in the form of capsules, tablets, soft gels, flex-tabs, fluid extracts, tinctures, ointments, powder, and sprays.  Many manufacturers of herbal products and dietary supplements sell Echinacea such as Nature's Way, Frontier Herbs, SOLARAY, and Futurebiotics.  For example, Nature’s Way markets Echinacea as a great product that is just like Penicillin.  “Echinacea helps support the body’s defense.  Echinacea is comparable to Penicillin in broad spectrum abilities” (  Also, Omnivit, another internet company markets Echinacea as the better that taken prescription drugs.  “Using immune stimulants if the quality is good is far better than taking drugs for long term” ( Herbal companies use many strategies to market their products. 


Be Careful What You Purchase!!!


Sometimes suppliers of Echinacea practice substitution.  Prairie Dock is sometimes sold as Echinacea.  Make sure check all labels for clear identification of plant genus.  Better yet, just READ ALL LABELS CAREFULLY!  Even when the genus is correct on the label there may be an absence of specific constituents.  “Labeling that lacks information should all be cause for care when purchasing” (


Is Echinacea Safe and Side Effects       


Overall, Echinacea is considered safe. It is well tolerated by most people. When taken as directed, little or no toxicity is associated with Echinacea use.  Echinacea may possibly be beneficial, in reducing duration and severity of symptoms.  Echinacea should not be used for auto-immune disorders such as tuberculosis and leucosis.  AIDS patients use of Echinacea is very controversial because not sure of its effects (  Other people that should not take Echinacea are those allergic to plants in the daisy family.  Prolonged use (more than eight weeks) is not recommended and may cause immune suppression or liver problems.  Echinacea should not be substituted for other medical treatments in very rapid infections.


Scientific Research


In March of 2003, the Archives of Internal Medicine published an article entitled "Echinacea and Truth in Labeling."  The purpose of this study was to assess the contents of Echinacea.  In the study, Echinacea preparations were obtained from different stores in Denver, Colorado in August of 2000.  Thin-layer chromatography was used to determine species and measure quantity.  From the chromatography, comparison of constituent to labeled content was assessed.  Also accuracy of species labeling was assessed.  The results of the experiment showed that 6 of 59 preparations contained no Echinacea.  Of the 21 standardized preparations, 9 met the standard on the label.  Basically this study showed Echinacea from retail stores often does not contain the labeled species. "A claim of standardization does not mean the preparation is accurately labeled, nor does it indicate less variability in concentration of constituents of the herb" (Gilroy 699).  Make sure read all labels very carefully and research marketers of Echinacea.


There are numerous clinical studies that show a great benefit of Echinacea in reducing severity of cold symptoms and duration.  Overall, at least a dozen clinical trials show that Echinacea prevents or treats upper respiratory tract infections.  In majority of cases, cold symptoms disappear 1-4 days earlier in subjects taking Echinacea.  There are also many studies that show no significant or measurable benefits of Echinacea.  It is strange because not one article scientific article was found on the effectiveness of Echinacea in my search.


In December of 2002, the Annals of Internal Medicine published an article called “the Treatment of Colds with a Capsule Form of the Herb Echinacea.”  The purpose of the study was to see if people taking Echinacea when their cold had a shorter duration and severity of the cold.  Students at the University of Wisconsin were recruited for the study as soon as they had their first sign of cold symptoms.  The students were either given Echinacea capsules or a placebo.  The students were to take the capsules three times a day until cold symptoms disappeared or for 10 days.  Each day students, filled out questionnaires about the severity of their colds.  The researchers found that Echinacea had no effect due to their comparison of time from questionnaires until all cold symptoms disappeared.  Basically, the researchers concluded that healthy young adults did not get any benefits from the Echinacea capsule.


Another study was done on Echinacea use in children.  The Journal of the American Medical Association published an article, “Efficacy and Safety of Echinacea in Treating Upper Respiratory Tract Infections in Children.  The purpose of the study was to see if “Echinacea Purpurea is effective in reducing the duration and severity of URI symptoms in children and assess safety in population.”  It was a randomized, double-blind, and placebo-controlled study.  Healthy children from 2-11 years old were recruited for the study.  Subjects received either Echinacea or a placebo and were studied from the beginning of symptoms until the cold ended or a maximum of 10 days, whichever came first.  Data was collected from 707 children with upper respiratory tract infections.  307 children received the placebo and 337 were treated with Echinacea.  There were no statistically significant differences between the two groups for duration and severity of symptoms.  The only difference between the two groups is that a rash developed much more in children that took Echinacea.  Therefore, Echinacea purpurea was not effective in treating children and caused an increased risk of rash.



Echinacea has a reputation as a therapeutic remedy and is easily available, because of this it will likely stay popular with the American public, despite some studies proving it ineffective.  Another benefit of Echinacea to the public is it is inexpensive, available over-the counter, and does not require a visit to the doctor’s office.  It is basically just self-care which is cheaper than seeing a doctor.  Also, since Echinacea has been used for many generations, peoples’ personal experience will continue to influence its popularity. Everyone should remember that Echinacea should not be viewed as a cure for common colds and flu.  It only reduces the severity and duration of symptoms not a curer of all.




Gilroy, C.M., Steiner, J.F., Byers, T, Shapiro, H, & Georgian, W.  (2003).            Echinacea and Truth in Labeling.  Archives of Internal Medicine, 163, 699-704.


Taylor, James A., Weber, Wendy, Standish, Leanna, Quinn, Hal, Goesling,              Jenna, McGann, Mary, & Calabrese, Carlos.  (2003). Efficacy and

          Safety of Echinacea in Treating Upper Respiratory Tract

          Infections in Children.  Journal of the American Medical Association, 290, 2824-2830.


Treatment of Colds with a Capsule Form of the Herb Echinacea.  Annals of           Internal Medicine.  2002, 137:1-18.


Yale, Steven H., Liu, Kejian.  (2004).  Echinacea Purpurea Therapy for the           Treatment of the Common Cold: a Randomized, Double-blind,           Placebo-Controlled Clinical Trial.  Archives of Internal Medicine,  164, 1237-1241.


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