Esculin (Esculoside), a coumarin compound derived from the horse chestnut and the traditional Chinese herbs such as Cortex Fraxini, has long been used for treating inflammatory and vascular diseases. The main activities of Esculoside focus on capillary protection, as it improves capillary permeability and fragility. It is reported to inhibit catabolic enzymes such as hyaluronidase and collagenase, thus preserving the integrity of the perivascular connective tissue. Esculin has various biological activities including anti-oxidant activity, intestinal anti-inflammatory activity, anti-cancer activity and growth inhibition of human leukemia cells. Esculin inhibits lipid peroxidation and scavenges hydroxyl radicals in the rat liver and exerts anti-inflammatory activity in both carrageenan- and zymosan-induced paw edema in mice. Esculin has the gastroprotective effect in cold-restraint stress and pylorus ligation-induced ulcer models. Esculin is used in a microbiology laboratory to aid in the identification of bacterial species (especially Enterococci and Listeria).