Is Echinacea the Feel-Good Herb of the Cold Season?

Margery Walsh swears by the herb echinacea. She keeps it handy during cold and flu season and begins taking it at the first sign of a cold.

“I find that it definitely lessens the severity of a cold,” the Westlake Village woman says. “It doesn’t keep me from not getting it, but I don’t feel like crawling under the covers.”

Walsh has plenty of company. Echinacea is one of the most popular herbal remedies in the United States: A recent poll found that 7% of Americans had used it. And it is estimated that consumers are buying up about $300 million worth of the herb annually.

But what are people getting for their money? Although there is some evidence that echinacea might reduce some symptoms of a cold, a new study and several recent analyses by researchers suggests the remedy may be greatly overhyped as a means to prevent colds and viruses.

According to several experts, the latest view on echinacea is that it may have a subtle effect at reducing the risk of developing a cold. But no one knows which of the many different preparations of echinacea is most effective.

“Patients should be aware that there is no convincing evidence for these products in general and that the products might differ strongly in their active ingredients,” says Dr. Klause Linde, a German researcher and expert on echinacea.

Others concur.

“Much more study on the efficacy of echinacea for various conditions must be carried out before a definitive statement about efficacy can be made,” said University of Tennessee researchers Julie L. Muller and Kevin A Clauson in a pharmaceutical journal.

And, said Dr. Lisa Corbin Winslow, in an article published last month in the Archives of Internal medicine: “Only a few clinical trials have been done with echinacea, and only a handful were well designed.”

But other experts, including Linde, say echinacea’s real value--although still not proven--may be in lessening the strength of a cold once it sets in.

“I would say that prevention trials on echinacea are mixed [in terms of results] and treatment trials tend to be more positive,” says Carlo Calabrese, a naturopath and co-director of the Research Institute at Bastyr University, a college of alternative medicine in Seattle.

Echinacea, also known as the purple coneflower, is a plant species found in North America and was very popular among Native Americans as a treatment for burns, snake bites, coughs and sore throats.

Based on this folklore, scientists have studied the plant in the laboratory and in animals and have identified several characteristics that seem to bolster the body’s immune system in fighting off infection.

However, from here the story on echinacea falters. Several of the first studies in humans are now considered seriously flawed, including a 1981 study that found the herb reduced the risk of infections by a whopping 49%.

The publicity over that study ignited a growing popularity of the herb in America and Europe in the 1980s and ‘90s. Moreover, echinacea appeals to consumers because it is purported to work to prevent colds while other over-the-counter cold remedies simply treat symptoms, Winslow says.

But the new analyses should serve to lower consumers’ hopes concerning echinacea.

A study published by Linde and colleagues last month in the Archives of Family Medicine confirms two other recent studies that suggest that echinacea may have only a minimal effect when taken to prevent a cold or virus.

German researchers at the Center for Complementary Medicine Research in Munich studied 302 volunteers from four military institutions and one industrial plant. The subjects were assigned to one of three groups: those who received daily drops of a species of echinacea called purpurea roots, those who received drops of a species called echinacea angustifolia roots or those who received a placebo, which is a harmless, ineffective solution. The volunteers, who were all healthy to begin the study, remained on the “treatments” for 12 weeks. The study included two of the three different species of echinacea that have been shown to have a medicinal value (E. purpurea, E. pallida and E. angustifolia).

The groups showed only slight differences at the end of the 12 weeks. In the E. angustifolia group, the time to the first infection was 66 days and, overall, 32% of the volunteers had an infection.

In E. purpurea group, the time to the first infection was 69 days, with 29.3% of volunteers having an infection.

And in the placebo group, the time to the first infection was 65 days and 36.7% had an infection.

The researchers concluded that the people taking echinacea had a 10% to 20% relative risk reduction. This means that if you have a 50% chance of catching a cold during the winter, taking echinacea might reduce your risk to 40% to 45%.

This benefit is so slight that researchers would have dismissed it as a fluke if not for one fact, Linde says.

“The results of two other trials are almost identical,” she noted. “So we tend to believe that there might be a small, real effect.”

Those other studies found relative risk reductions of 14% and 15%.

Even drawing conclusions from these three studies is a problem, however, because each study used a different preparation of echinacea (none of which is commonly available in the United States). Preparations can vary depending on which part of the plant is used: roots, herb or both. There are also different methods of extraction, such as pressed juice or alcoholic extraction.

“Echinacea species have quite different contents of the potentially active ingredients, and this suggests that there should be differences [in effectiveness],” Linde says.

Calabrese, who has recently finished a study on echinacea but cannot yet release the results, recommends consumers look for information on the label that describes the product as being made from the juice of the fresh above-ground plant. He also recommends taking the full, recommended dose at the first signs of a cold.

“Some people say that the alcoholic extract does not have all of the components that stimulate the immune system,” he says.

Researchers have not identified a particular active ingredient or dose that each product should contain to assure the best chance of benefit, a process called standardization.

Echinacea is also often combined with other herbs, most often goldenseal. Researcher Mary Ann O’Hara of the University of Washington recently published an article discouraging the use of goldenseal because of scant evidence that it works to prevent colds and because it is an endangered species.

Almost all experts agree that echinacea should not be taken on a regular basis, such as over the course of the winter. German health authorities have cautioned against long-term use of echinacea because it might weaken the immune system, O’Hara says. German guidelines also discourage the use of echinacea in place of antibiotics. And while there is little to suggest there are any major safety issues surrounding echinacea, health experts say the herb should not be taken by anyone with autoimmune disorders, HIV infection, tuberculosis or multiple sclerosis.

Echinacea taken on a limited basis has a very good safety record, and some experts suggest it’s worth trying, given its relatively low cost. Linde notes that one mysterious finding in the recent study was that people in the echinacea groups perceived they had benefited more than the people taking the dummy solution. None of the subjects knew which treatment they were actually getting.

It’s possible that simply believing something is working may have a power of its own. Linda Buckley, 31, of West Los Angeles, says it doesn’t matter to her that the scientific evidence on echinacea is unconvincing. She believes that it has protected her through four cold and flu seasons.

“It absolutely helps. And all I care about is that it works,” she says. “There isn’t too much scientific study on any supplements. I also don’t like taking antibiotics. I don’t think they’re that good for you. I’d rather take something natural first.”