菘蓝（学名：Isatis tinctoria），又名欧洲菘蓝、草大青、大蓝、大靛、大青等，属十字花科植物。

一年生或二年生草本；长椭圆状椭圆形基出叶较大，具有柄；长椭圆状披针形茎生叶，基部箭形，半抱茎，全缘或有不明显的细锯齿；夏季开黄色小花，总状花序，在枝端合成圆锥花序；长椭圆形扁平角果，边缘呈翅状，有短尖；有一种子。

Isatis tinctoria, with woad (/ˈwoʊd/) or glastum as the common name, is a flowering plant in the family Brassicaceae. It is commonly called dyer's woad. It is occasionally known as Asp of Jerusalem. Woad is also the name of a blue dye produced from the leaves of the plant.