龙胆（学名：Gentiana scabra）为龙胆科龙胆属的植物。

多年生草本。卵形至披针形叶子对生，有1或3条主脉；秋季开蓝紫色花，聚伞花序顶生。

Gentiana scabra (or Japanese gentian) is a species of flowering plant in the Gentian family (Gentianaceae), found in much of the United States and Japan. The flowers bloom in mid-summer, autumn and are blue or dark blue in color.