Nattokinase is an enzyme extracted from a popular Japanese food called natto. Natto is boiled soybeans that have been fermented with a bacterium called Bacillus natto. You won’t find nattokinase in soy foods other than natto, since nattokinase is produced through the specific fermentation process used to make natto. Natto has been used as a remedy cardiovascular disease for hundreds of years. Nattokinase, the chemical in natto that is probably responsible for its effects, was discovered by a University of Chicago researcher, Dr. Hiroyuki Sumi. Nattokinase is used for cardiovascular diseases including heart disease, high blood pressure, stroke, chest pain (angina), deep vein thrombosis (DVT), “hardening of the arteries” (atherosclerosis), hemorrhoids, varicose veins, poor circulation, and peripheral artery disease (PAD). It is also used for pain, fibromyalgia, chronic fatigue syndrome, endometriosis, uterine fibroids, muscle spasms, infertility and cancer. How does it work? Nattokinase decreases the ability of blood to clot. This “thins the blood” and might protect against conditions caused by blood clots such as stroke and heart attack.