Natto-Serra is a combination of two natural enzymes that have been used as dietary supplements for decades. Serrapeptase (serratio-peptidase) is a protein digesting enzyme isolated from the friendly bacterium Serratia E-15 discovered in the Japanese silkworm. Nattokinase also digests protein and is derived from natto, a fermented soy food popular in Japan for centuries. This nattokinase is free ofIngredients:Supplement FactsServing Size: 1 Veggie CapsuleAmount per serving% Daily ValueCalcium (from tricalcium phosphate and calcium stearate in Serrateric)29 mg2%Serrapeptase Enzyme (from Serratio sp.)40,000 SPU**Nattokinase (from fibrinase enzyme)2,000 FU*** Daily Value not established.**SPU-serratiopeptidase activity units***FU-fibrinolytic activity unitsOther Ingredients: Serrateric (maltodextrin, tricalcium phosphate, calcium stearate, medium chain triglycerides), delayed release capsule (hypromellose, gellan gum, purified water).Contains Soy.