Ginkgo Biloba a Dud for Alzheimer’s: Ethical to Keep Selling It?

What would you if you woke up one day and someone had proven that the product you manufacture or market or sell just doesn’t work. That’s roughly what happened recently to people who market remedies for Alzheimer’s Disease based on the popular herbal ingredient ginkgo biloba.
Here’s the story, courtesy of the Sacramento Bee: “UC Davis researcher finds no effect from ginkgo biloba.”

The world is a complicated place, and the effects of many products is hard to evaluate — hard for consumers and sometimes even hard for manufacturers. I suppose we could think of several epistemic categories:

  • Products we know generally work for their intended purpose (e.g., knives for cutting, antibiotics for bacterial infections),
  • Products we know don’t work (antibiotics for viruses, and now ginkgo biloba for Alzheimer’s)
  • Products we’re (collectively) unsure about.

I suppose lots of herbal remedies fall into the latter category. If some herb has been used “for centuries” as a medicine by some culture or another, but has never been rigorously tested, it’s maybe not crazy to think it has some effect, but it’s foolish to profess certainty about it. But it might not be crazy for a company to say, in effect, “Hey, look, we think there’s some evidence our product is useful. If you agree, try it out. No guarantees.” But once that product has been demonstrated not to work, then what? Presumably the ethical company has to stop marketing it.

On the other hand, I’m guessing that many buyers and sellers of herbal remedies would reject the scientific — some would say scientistic — framework that allows the researchers who conducted the study referred to above to say, with such certainty, that ginkgo biloba just doesn’t work. Science, they might say, has its limits. There are ways of moving through life other than living by the edicts of scientists. Fair enough. But as a society, we also want to have some reasonable assurance that companies selling products (in this case, herbal products) aren’t pulling a fast one, taking advantage of naive, sometimes-uncritical consumers. And the only way to do that is to hold them to standards such as requiring commercial claims to be capable of being evaluated in publicly-accessible ways. Scientific methods fit the bill. Scientists never say, “I just know this…so trust me.” They say “here’s the evidence, here’s how I got it, and here’s how you can check my work.”

Any product that could be tested that way should be tested that way. And any product that fails the test, probably shouldn’t be sold.

See also this blog entry from a few weeks ago: Marketing Useless (Magnetic) Products.

Relevant book to suggest: Complementary and Alternative Medicine: Ethics, the Patient, and the Physician and Herbal Medicine: Chaos in the Marketplace and Snake Oil Science: The Truth about Complementary and Alternative Medicine.

4 comments so far

  1. Alzheimer's Team on

    I always enjoy your blog.

  2. George on


    I read your article as I was searching for something to help with an elderly relative who has fallen victim to AD.

    After a long career in scientific research, I have to say that your article is – to use the non-scientific expression – a load of crap. Your ‘big lettered’ headline promises to reveal something informative. Instead, the whole article just waffles on based on a page which is no longer accessible. If you did your own research you would have a greater understanding of the complexity of AD and of the existing benefits (and potential promise) that Ginkgo Biloba and similar naturally occuring medicines provide.

    So get real sonny, and don’t bother posting blogs on something you’re not knowledgeable.

    Yours, etc.


    • Chris MacDonald on


      If you know of high-quality scientific work that contradicts what I wrote, please cite it. I’m always happy to learn of new developments. When I wrote the above blog entry in 2008, it reflected (admittedly 2nd-hand) the very best available scientific evidence. If new, solid evidence has arisen since then, I would be very happy to know it.


  3. […] Ginkgo Biloba a Dud for Alzheimer’s: Ethical to Keep Selling It? November 25, 2008 […]

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