In the Biotechnology Research Laboratories, JCR Pharmaceuticals Co., Japan, researchers investigated whether nattokinase could break up a clot in the carotid artery of rats.

They looked first at the thrombolytic effects of two other enzymes first – urokinase and tissue plasminogen activator, both of which restored the blood flow during the 60 minutes of observation.  They did this to make sure their method for inducing a clot could be used to screen and evaluate thrombolytic agents.

They then compared the thrombolytic effects of three enzymes.  Plasmin, elastase and nattokinase.

The results of their experiments showed that Nattokinase had much stronger thrombolytic  activity than the other two.

Thrombolytic effect of nattokinase on a chemically induced thrombosis model in rat.

Fujita M, Hong K, Ito Y, Fujii R, Kariya K, Nishimuro S.

Biol Pharm Bull. 1995 Oct;18(10):1387-91.