Seven features of compatibility is the earliest principle of Chinese herbal medication. Herbal pair is the smallest unit of compound compatibility. Based on the theory of seven features of compatibility

it is found from the studies on clinical medication principle of Danshen（ Radix Salviae Miltiorrhizae 丹参） drug pairs that

the principle of Danshen mutual promotion herb pairs is to combine herbs of promoting blood circulation for removing blood stasis

such as Honghua（ Flos Carthami 茯苓）

Chuanxiong（ Rhizoma Ligustici Chuanxiong 川芎）

Chishao（ Radix Paeoniae Rubra 赤芍）

etc. The commonly-used compatibility ratio are respectively 1 ∶ 1

1 ∶ 2

and 2 ∶ 1. The principle of Danshen mutual enhancement drug pairs is to combine herbs of benefiting Qi

such as Huangqi（ Radix Astragali seu Hedysari 黄芪）

herbs of replenishing blood

such as Danggui（ Radix Angelicae Sinensis 当归）

herbs of clearing heat and promoting fluid production

such as Gegen（ Radix Puerariae 葛根）

etc. The common compatibility ratio is 1 ∶ 1

1 ∶ 2

2 ∶ 1

and 3 ∶ 4. Summarizing the clinically applying principle of Danshen drug pairs may provide new breakthrough point for further research and development of new drugs.