Nattokinase is an enzyme that supports normal, healthy blood flow and circulation. Nattokinase is an enzyme extracted from Natto, a cheese-like food made from fermented soybeans. Nattokinase may contribute to the regular healthy function of the heart and cardiovascular system by enhancing fibrinolytic activity. Each capsule contains 100 mg Nattokinase NSK-SD (20,000 fibrinolytic activity per gram). 60 vegetarian capsules per bottle. NSK-SD is a registered trademark of Japan Bio Science Laboratories. People with ulcers, recent or pending surgery, or recent major trauma should not take Nattokinase. Generally, people with bleeding disorders, or taking prescription blood thinners, should use this product only under the close supervision of a medical doctor.