Huang Qin (Scutellariae Radix) is a medicinal that comes in two common forms. Within the field of pharmacy, these two forms are known as Tiao Qin (young scutellaria) and Ku Qin (old scutellaria). They are generally used interchangeably in the average clinic, but the two forms are said to have different advantages and they are often differentiated in trade.

The thin, dense form is called Tiao Qin. It comes from younger roots and is heavier in weight. Tiao Qin is said to be more sinking in its medicinal action, and it is thus preferred for cases of damp-heat in the intestines.

Tiao Qin often appears slightly greenish. The specimen pictured above is a representative example. According to pharmacy experts, the greenish color is produced by excessive moistening during the cutting process. The green color it is considered to be a flaw that results from imperfect cutting technique, and it corresponds with reduced baicalin content. Good cutting technique, particularly by cutting fresh roots instead of re-hydrating dried roots, minimizes this oxidative change and keeps the color more yellow. Traditional pharmacists prefer Huang Qin that is more yellow and less green, though in clinical practice both forms are common.

In comparison, Ku Qin is larger, less dense, and tapered. The superior portion of the root is relatively wide and tapers down to a comparatively narrow inferior tip. There are small holes in the root body, and the appearance is generally more yellow and less greenish. The cortex of the root is also more obvious. Ku Qin is thought to be more light and floating, so it is traditionally regarded as the superior form of Huang Qin for the treatment of lung heat.