Baicalin is a flavonoid compound found in the roots of Scutellaria baicalensis, a traditional Chinese herb. Baicalin impurities refer to the various other compounds that may be present alongside baicalin. These impurities can affect the purity and quality of baicalin, and therefore must be closely monitored and controlled in the production process. Common baicalin impurities include baicalein, wogonin, and oroxylin A.