Echinacea and the Common Cold

I woke up yesterday morning with a brutal cold. Before I began to learn how to use reason and how to look for the evidence, I would just take health care advice based on popular belief. Something I hear all the time, and something that I used to repeat myself, is that you should take echinacea to fight a cold and to boost your immune system.

But if echinacea is so effective, why isn’t there any in my NyQuil?

According to the Wikipedia entry on echinacea, the idea that echinacea helps treat the common cold began when a Swiss herbal supplement maker was incorrectly told that Native American tribes in South Dakota used it for cold prevention.

But despite its questionable beginnings as a cold medicine, it has still become an extremely popular remedy, at least among my friends and family. So is there evidence behind echinacea to convince me that it is efficacious?

This University of Connecticut study claims that “Echinacea, the most popular herbal supplement in the United States, cuts the chances of catching the common cold by 58 percent and reduces the duration of the common cold by 1.4 days.” Sounds good to me! Unfortunately, this study has come under a lot of criticism.

The problem is that it’s a meta-analysis of smaller studies. Meta-analyses can be useful, however in this case critics say that the smaller studies are too dissimilar to be used accurately in a meta-analysis, so this study is not reliable enough to be taken as solid evidence for the efficacy of echinacea.

The gold standard of evidence in medicine is the large, placebo-controlled, double-blinded study. The closest to this type of study that has been done on echinacea is this one, done by the University of Virginia:

In one of the largest, multi-center clinical trials to study the effectiveness of the popular herbal cold supplement, Echinacea, researchers at the University of Virginia Health System have found that it has no effect on treating the common cold.

Turner and colleagues tested the efficacy of Echinacea on 399 volunteers between 2002 and 2004. The volunteers tested were recruited from UVa and were all susceptible to an experimental cold virus, rhinovirus type 39. They were divided into seven different groups and exposed to the cold virus through the nose.

Each group then received either a placebo or one of three possible Echinacea treatments (extracts of the herb originally used by Native Americans and endorsed by the World Health Organization for cold treatment). Volunteers were ‘blinded’ and did not know what treatment they were given. After five days of being studied in an isolated setting, there were no significant effects with Echinacea on the rates of infection or the severity of cold symptoms seen among the study participants. About ninety percent of all participants were infected with the cold virus.

“The results of this study demonstrate that, as tested, the putative active constituents of E. angustifolia do not have clinically significant effects on rhinovirus infection or illness,” Turner wrote in the study.  Researchers from Karl-Franzens-Universitaet in Graz, Austria; the Medical University of South Carolina and Clemson University collaborated on the research.

So no good evidence yet that echinacea does anything for the common cold.

This large trial has also come under criticism, however this time from Dr. Michael Murray, a manufacturer of echinacea. He says that the study used the wrong type of echinacea and in the wrong dosages.

I wonder why Dr. Murray hasn’t funded a study himself to prove the effectiveness of the herb? If he’s so confident in its efficacy then he would be doing himself a favour by proving that it works. Echinacea would become a part of mainstream medicine if it were shown to be effective, it would be recommended by doctors, and Murray would be able to manufacture and sell more.

For now, the burden of providing evidence lies with its advocates. Until they provide reliable evidence that shows that echinacea is good for my health I’ll continue taking my NyQuil to alleviate my cold symptoms, which is proven by science and which outlines its possible side-effects on the box so I can be informed as to any risks it may carry (unlike my bottle of echinacea pills).

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9 Responses to “Echinacea and the Common Cold”


  1. 1 Global Villager June 7, 2009 at 11:03 pm

    Hmmmm, good post, but I think I will still take Echinacea for the hell of it. If it works then great, if it doesn’t I don’t see what harm the herb will do! It makes me feel better mentally to take it so that is half the battle in my opinion!

  2. 2 linzeebinzee June 7, 2009 at 11:11 pm

    Why take it though if there’s nothing to back it up? I don’t understand that. Why waste your money on something that’s yet unproven by science? If you want to avoid getting a cold wash your hands often, and if you want to alleviate cold symptoms take something that’s proven to work. There’s no sense spending your hard earned money on something that you only think might have an effect because lots of people say it does.

  3. 3 Global Villager June 7, 2009 at 11:27 pm

    The mind is a powerful thing – my imagination is particularly strong, I can convince myself that I am sick or have a disease, unfortunately it happens often (runs in my family). At the same time, I can convince myself that something works too, and I feel better when I take echinacea, I feel like I am doing something about it and it helps me to believe I am feeling better. I have felt better after taking it…..it may not have done anything, I know rationally this might be the case.

    I agree with you, the “bandwagon effect” is not a good reason to do something. However, this has less to do with others and more to do just with my beliefs.

  4. 4 Scott June 10, 2009 at 10:21 pm

    Nice post. Echinacea was huge in pharmacies a fad a few years ago. Now it seems people have moved on to Cold-fX – probably because there’s a lot of marketing behind it.

    BTW the data supporting NyQuil isn’t that great. The ingredients have been around for years, and the quality of data supporting their use isn’t fantastic. The decongestant probably works, but the other ingredients really haven’t been shown to be that effective. I did a post on this, focused on kids:

    http://sciencebasedpharmacy.wordpress.com/2009/05/19/cough-and-cold-products-for-children/

  5. 5 linzeebinzee June 10, 2009 at 10:36 pm

    Cold-fX…I’ve heard my mom talking about that before, hadn’t looked into it until now…ginseng eh?…another product to “boost your immune system”…

    Thanks for the info on NyQuil!

  6. 6 croz´ June 20, 2009 at 2:42 pm

    I take nothing that comes out of the pharmaceutical medicine chest for a cold, a headache or any other day to day ailment for which prescribed and over-the-counter ´remedies´ amass financial fortunes. I simply do not trust them or approve of their methods, profiteering and lamentably-shallow trials.

    Echinacea is natural, not synthesised – I know, you could say the same of hemlock – but for some, it works; and it it does not require a clinical trial or scientific evidence for someone to know when they are feeling better.

    Honey is one of natures wonder cures. It does not spoil, it is a topical and oral remedy and I eat it evry day. I don´t get colds, flu, rarely headaches or other minor ailments.

    The problem with many, and the US is chronic in this regard, is the dependency on medication for everything. Even when people are healthy and normal, they are scared into believing the contrary. Drug advertising frequency in the US is obscene.

    There is no sense in spending your hard-earned money on something just because soemone in a white coat, with a hollywood smile, says is it is good for you.

  7. 7 Scott June 21, 2009 at 5:28 pm

    It’s termed the “naturalistic fallacy” – the believe that anything “natural” is good for you yet anything “synthetic” is harmful and bad. A common belief, but it’s fundamentally flawed.

    We need to consider the evidence supporting any product. Whether it’s naturally sourced or not is irrelevant when considering efficacy and safety. Botulism and mercury are natural substances too.

  8. 8 linzeebinzee June 22, 2009 at 7:18 pm

    So you don’t think that the people selling herbal remedies “amass financial fortunes”? The difference with the people selling herbal “remedies” is that they aren’t restricted by having to actually prove that the “remedies” work.

    I second what Scott said about the thinking that natural means good. Maybe you should take some cyanide, that’s a natural substance too. (Disclaimer: cyanide is poisonous, I don’t actually want you to take it, just making a point).

    Your tendency to attribute your good health to honey and echinacea is just confirmation bias. You think that taking natural remedies is keeping you healthy, but correlation is not necessarily causation. You might be just as healthy if you didn’t eat honey. This is why scientists perform large placebo controlled clinical trials to see whether something works: to figure out whether the honey (or whatever) is having an effect.

    The last sentence in your comment is funny to me, because that’s what I frequently see in commercials for alternative “remedies”: someone in a white coat, a hollywood smile, saying it is good for me. When I see conventional medicines advertised, they don’t sensationalize what the medication can do, they list all of the possible side effects and urge the consumer to talk to their doctor. It’s not very glamerous, but it is responsible.

  9. 9 Global Villager June 24, 2009 at 6:40 pm

    I am on the side of hunkering down, biting your lip, and riding it out sans remedies. It develops character and boosts your immune system, especially if you are young.


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