Nan Shele, commonly known as "Old Crow Pillow". It is the seed of the leguminous plant Caesalpinia minax Hance. Mainly produced in Guangxi, Yunnan and other places. It is generally oval or oblong, with blunt ends at both ends, 1.2-2.2cm long, 0.7-1.2cm in diameter, black or dark brown on the surface, sometimes with transverse rings or cracks, and there are stalk residues at the base. Next to it is a small circular chalaza. The texture is hard and extremely difficult to break. The seed coat is about 1mm thick, and the inner surface is grayish-yellow, smooth and shiny. After removing the seed coat, 2 cotyledons can be seen, which are brown, thick, oily, and have a gap in the center.

Nature, flavor and function: The qi is weak and the taste is extremely bitter and pungent. Good at treating bruises and relieving pain.

Main ingredients: Mainly containing anthraquinone compounds.