Can rhizoma chuanxiong replace radix Angelica sinensis in the traditional Chinese herbal decoction danggui buxue tang?

Herein, we test the hypothesis that a member of a formulated Chinese herbal decoction cannot be replaced by another herb. Danggui Buxue Tang (DBT) is being used as an example for illustration: this is a traditional decoction containing Radix Astragali (RA) and Radix Angelicae Sinensis (RAS) in a weight ratio of 5 to 1. Rhizoma Chuanxiong (RC) and RAS are two chemically very similar herbs but with a distinct function.