[Historical and herbalogical studies on coloring crude drug (Part 1): "Langbacao"]

The name of Langbacao was described for the first time in Kai Bao Ben Cao in 10th century, in which Langbacao was introduced as an herb medicine for scours. While, as the name of Qu, Wujie, it was first described in Er Ya and as the name of Langyecao, it was first described in Ben Cao Shi Yi. Many investigators have confirmed that the original plant of Langbacao is to be Bidens tripartita L. In Japan, Langbacao is generally recognized as ta-u-ko-gi, while some investigators suggested that it is unlikely that ta-u-ko-gi is identical to Langbacao. In the old Chinese literature, Langbacao had been mentioned as a dye which could make hair dark. But in modern Chinese and Japanese literature, few papers reported the use of Bidens tripartita L. as a dye. The characteristics of the shapes of Langbacao between old and modern literature seem not to be consistent. Other names of Langbacao are confused even in the modern literature. It seems that Langbacao in the old literature includes species of the genus Bidens other than B. tripartita.