Hirudin extract (also known as hirudin powder) is the most important active ingredient in leeches, dried leeches extract and its salivary glands, and is a small molecule protein (polypeptide) composed of 65-66 amino acids. Hirudin Hirudin extract contains rich hirudin, hirudin has a strong inhibitory effect on thrombin, is the strongest natural specific inhibitor of thrombin.