Serrapeptase, 40 000 SPU promotes and maintains healthy sinus and airway function as well as a healthy immune response. Serrapeptase is a proteolytic enzyme that comes from the Serraitia bacteria species strain E15. It helps dissolve hard particles made of protein that cause unwanted side effects from toxins, scar tissue, blood clots and cysts. As serrapeptase can be destroyed by stomach acids, Doctor's Best Serrapeptase uses Serrateric, a coating that protects the enzyme until it reaches the intestines and therefore optimizes absorption. It is recommended to take 1 capsule daily with at least 8 oz. of water on an empty stomach, or as recommended by a nutritionally-informed physician. Not recommended for individuals who are pregnant, nursing, taking blood thinners, or have poor digestion. Stop taking if you experience nausea, vomiting, or stomach upset. Store in a cool dry place.