Natto is the only food source of nattokinase, but you can also buy it as a supplement. Research suggests that supplement intake is just as effective as consuming natto. Nattokinase might lower blood pressure. Taking nattokinase along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure

Because of increasing interest rein nattokinase, methods of production that increase yield and stability have been explored. For example, irradiation of the bacterial strain B. subtilis natto Surgery: Nattokinase might increase the chance of bleeding during or after surgery. It might also make blood pressure difficult to control during surgery.