Nattokinase is an enzyme that is extracted from “natto”, a traditional Japanese food made from fermented soybeans. It has been found to have fibrinolytic (fibrin-dissolving) properties, which makes it useful in the prevention of blood clot formation. Learn more about Serrapeptase, its uses, contraindications, proper dosage, and several pharmacy-grade brands recommended by Dr. Kristina Carman with this helpful guide.