Robert,
I has to do with thinning the blood too much – or at least the potential to do so. Overall, the caution is primarily with Coumadin.
The product you listed looks very interesting. It should be fine.
Here is the deal with Coumadin. It has a long-list of contraindications. Some doctors even recommend avoiding broccoli while on Coumadin. However, patients who are on Coumadin have a blood test called an INR to determine their range of acceptability. It is certainly acceptable to have a patient on a healthy diet, or even products like biofilm enzymes, but to check their INR’s and adjust Coumadin accordingly.
Dr. Woeller