Rhizoma Corydalis. Part used: Rhizome. Known as Corydalis Rhizome. Entering meridians: Heart, Liver and Stomach. Yan Hu Suo invigorates the blood, circulates Qi, stops pain, disperses extravasation and induces and prolongs sleep. All Phoenix Medical dry authentic herbs and concentrated herbal granules are free of sulphur, herbicides and pesticides.