You have to be careful when evaluating all studies with ginkgo, because as mentioned in the first paragraph, there is variation from batch to batch even with the same product. Therefore, if a study used only one batch, it only means that there was not enough of the terpenoids in that batch to cause no harm. It cannot be inferred that there will not be enough terpenoids in another batch or brand to cause harm.

The bottom line is that although "natural" products may have some health benefits, they are poorly studied, poorly understood, and poorly monitored. Even products that have been USP verified may be dangerous. Especially if you are on warfarin (brand name Coumadin), you should talk to your doctor before starting any dietary supplement or natural remedy.

The ClotCare International Registry of Interactions Between Oral Anticoagulants and Dietary Supplements is now available online. At this time, anticoagulation clinicians are invited to begin using the registry to report observed interactions between warfarin and dietary or herbal supplements. The system will ask the reporting clinician to check responses to several questions in order to grade the strength of the data being reported. Development is currently underway to make this registry searchable so that cases reported may be reviewed by others.

Henry I. Bussey, Pharm.D., FCCP, FAHA. February, 2008

Am Fam Physician 2003;68:114-6. Copyright© 2003 American Academy of Family Physicians. The herb black cohosh, or Actaea racemosa (formerly named Cimicifuga racemosa), is native to North America. The roots and rhizomes of this herb are widely used in the treatment of menopausal symptoms and menstrual dysfunction. Studies have demonstrated that this botanic medicine, when standardized properly to the terpene glycoside fraction, appears to be effective in alleviating menopausal symptoms. Adverse effects are extremely uncommon, and there are no known significant adverse drug interactions.

Ginkgo has been shown to improve symptoms of impaired arterial circulation: In patients with hardening of the arteries of the legs (= arteriosclerosis) patients treated with ginkgo can walk farther without pain than patients treated with placebo (reference 1). However, Ginkgo has not been compared in efficacy to aspirin or any other pharmaceutical anti-platelet agent, such as Plavix®, Tiklyd®, or Aggrenox®. Up to this point there are no published studies of the use of Ginkgo in the treatment or prevention of stroke. I would not count on it having sufficient effect to prevent stroke or heart attacks. I would clearly not recommend it as sole treatment for a TIA. Last Updated: 3/14/07

Wednesday, August 31, 2005 - Page updated at 12:00 AM By Kyung M. Song Seattle Times staff reporter

DHEA may increase the risk of blood clotting. Patients who take anticoagulants (blood thinners) or antiplatelet drugs (such as aspirin) to prevent blood clots should discuss the use of DHEA with a healthcare professional. Examples of blood thinning drugs include warfarin (Coumadin®), heparin, and clopidogrel (Plavix®). The risk of blood clots is also increased by smoking or by taking other hormones (such as oral contraceptives or hormone replacement therapy), and these should not be combined with DHEA unless under medical supervision.

I think it is fair to conclude at present that Nattokinase may have some potential to protect from blood clots. However, it has not been appropriately studied in humans. Nattokinase is not a substitute for warfarin! If you take it - don't count on it having any clinical effect. It has also not been studied regarding its safety profile, particularly when it is taken together with warfarin or aspirin. The FDA concluded in 2002 that there is no "adequate basis to conclude that NKCP [Natto extract] containing 0.01 % of Nattokinase enzyme is reasonably expected to be safe" and that "there is inadequate information to provide reasonable assurance that such ingredient does not present a significant or unreasonable risk of illness or injury" [reference10]. Furthermore, the FDA has warned as recently as September 21, 2006, that unsubstantiated and illegal claims are being published about the effectiveness of NSK-SD Nattokinase (ref. 11). Other health care professionals have also concluded that there is an absence of data at this time that Nattokinase has clinical effectiveness (ref. 12). Last Updated: 3/18/07

Copyright © 2007 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. Studying effectiveness of DHEA for SLE is difficult, reflecting the problems of studying any treatment for a disease as complex as SLE. From the seven RCTs to date, there was evidence that DHEA had a modest but clinically significant impact on health related quality of life in the short term. Impact on disease activity was inconsistent, with DHEA showing no benefit over placebo in terms of change in SLEDAI in all but one of the 6 studies reporting this outcome. Long term outcomes and safety remain unstudied.

However, no clinical trials have been done to determine whether nattokinase can prevent thromboembolism in humans. Nor is it clear from its known physiological effects whether one could expect nattokinase to be a reasonable alternative to warfarin. First, the fibrinolytic effect of nattokinase is relatively modest. Second, its "blood thinning" effect is mediated by a different mechanism of action than that of warfarin. Fibrinolytic agents promote the dissolution of clots once they have already formed, whereas warfarin prevents the formation of clots by inhibiting the activation of blood-clotting proteins. Because there are so many unknowns, it would be dangerous to assume that nattokinase is a clinically effective alternative to warfarin.

Written by: Stephan Moll, MD "Nattokinase is not a substitute for Warfarin! If you take it – don't count on it having any clinical effect. It has also not been studied regarding its safety profile, particularly when taken together with Warfarin or aspirin. "

Marie B. Walker Henry I. Bussey, Pharm.D., FCCP, FAHA Ann K Wittkowsky, PharmD, CACP, FASHP, FCCP May, 2007

The ClotCare International Registry of Interactions Between Oral Anticoagulants and Dietary Supplements is now available online. At this time, anticoagulation clinicians are invited to begin using the registry to report observed interactions between warfarin and dietary or herbal supplements. The system will ask the reporting clinician to check responses to several questions in order to grade the strength of the data being reported. Development is currently underway to make this registry searchable so that cases reported may be reviewed by others.