Where is the main producing area of yanhusuo? What is the effect and effect?

Rhizoma Corydalis, also known as Yuanhu, Xuanhu, and Atractylodes macrocephala, Paeonia lactiflora, Fritillaria, etc., are also known as Zhejiang Bawei. So, where is the main producing area of yanhusuo? What is the effect and function of Rhizoma Corydalis? Does Rhizoma Corydalis have side effects? Where is the main producing area of yanhusuo? The main producing area of Corydalis yanhusuo