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Gingko biloba and possible links to Thyroid and Liver Cancers

Gingko biloba and possible links to Thyroid and Liver Cancers

Gingko biloba extracts are frequently mentioned across the various herbal/alternative medicine sites. Indeed, I have been tempted to try it myself for a non-thyroid reason. So any concern over its safety has to considered carefully.

This paper comes from a reputable source and suggests the very serious possibility that extracts of Gingko biloba actually cause cancer of the thyroid and liver in mice and rats.

Far from proof that it does the same in humans, but enough of a red flag to raise concerns.



March 2013

NTP TR 578 NIH Publication No. 13 - 5920

National Institutes of Health

Public Health Service



Extracts from leaves of the Ginkgo biloba tree are used as an herbal remedy and dietary supplement purported to improve memory and brain function. We studied the effects of ginkgo biloba extract on rats and mice to identify potential toxic or cancer-related hazards.


We deposited solutions containing Ginkgo biloba extract in corn oil through a tube directly into the stomach of male and female rats and mice five times a week for two years. Groups of 50 male and female rats received 100, 300, or 1,000 milligrams of Ginkgo biloba extract per kilogram of body weight, and groups of male or female mice received 200, 600, or 2,000 mg/kg each day. Similar groups of animals were given solutions of corn oil with no chemical added and served as the control groups. At the end of the studies, tissues from more than 40 sites were examined for every animal.


Every group of animals exposed to Ginkgo biloba extract experienced increased rates of a variety of lesions in the liver, thyroid gland, and nose, and male and female mice also experienced several different lesions in the forestomach. These lesions included hypertrophy in the liver and thyroid gland in rats and mice, liver hyperplasia in male and female rats, hyperplasia and atrophy of the epithelium within the nose of male and female rats, and inflammation, hyperplasia, hyperkeratosis, and ulcer in the forestomach of male and female mice. In addition, increased incidences of cancers of the thyroid gland were seen in male and female rats and male mice and liver cancers in male and female mice.


We conclude that Ginkgo biloba extract caused cancers of the thyroid gland in male and female rats and male mice and cancers of the liver in male and female mice.


Picture is of a Gingko biloba

7 Replies

How worrying for those taking ginko believing it is helpful, especially for memory problems.


And especially for those in whom it really does seem to be having a positive effect. How on earth to balance a cancer possibility (unproved but suggested) against a known positive improvement?

I hate it when I find things like this!


It's like one step forward - two back.


I am not sure I would lose too much sleep over that if I felt I really needed it's positive benefits, and at the same time, I would be less inclined to use it if I didn't - Don't see it as any different to any other drug or supplement there is... almost everything has some drawback, some minor some serious - eg. I take NSAIDs... or I can't get out of bed in the morning, but they have a known tendency to cause heart problems, they raise blood pressure, and can cause kidney failure (I have some protein in my urine already, probably caused by this). Opiates - they keep me going, and I suspect without them I might have ended it all years ago - but they have caused MAYHEM to my Endocrine system and many of the drugs I take are to counter the issues from the pain relief! I only take them because I need them to get on with my life, I am surte I wouldn't if I didn't :-(

At the moment I am dealing with Prostatic hypertrophy, and the drugs I can get prescribed have notorous severe side effects, which I want to avoid if at all possible... similarly I can't take one of the herbal alternatives (well known to work well) but as I take prescription drugs which in combination with that will possibly cause blood clotting issues... now, do I try them or do I not? I have to try and sort out the best options for me using those treatments likely to have the least negative impact :-(

Booze... look at the many risks involved with drinking, all very well know... yet I hardly know anyone who doesn't drink a good bit, and plenty drink to excess.

Like everything else, you weight up the risks to the benefit, and the point where that balances out will differ for everyone.

Knowledge is power, but at times it also goes a long way to winding us up too :-(


Those poor rats!


I seriously question the validity of this study and it's findings. The quantity of Ginko Biloba given each animal is way beyond what is even recommended for humans. Years ago, there was a study done on lab rats with broccoli. The findings from that study showed the rats got cancer from broccoli! How much were they given, you ask?... 500 times the amount they would normally consume in a one week period! Wow! Shock of shocks! You can get cancer from anything is not taken in moderation. Sorry, but this "study" doesn't wash.


I note also the gingko extract was added to corn oil, probably gmo corn oil, which is just as likely to be the culprit as much as anything


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