Nattokinase Extract is an enzyme extracted and purified from a Japanese food called Natto. Natto is a food made from fermented soybeans that has been eaten in Japan for many years. Natto is produced by fermentation by adding the bacterium Bacillus natto, a beneficial bacteria, to boiled soybeans. The resulting nattokinase enzyme is produced when the bacterium acts on the soybeans. While other soy foods contain enzymes, it is only the natto preparation that contains the specific nattokinase enzyme.