n.复染剂；复染色( 指作显微镜观察时使用的一种通过第二次染色使生物标本显示不同颜色的染色剂)
Gram negative bacteria (e.g.Cyanobacteria) are decolorized, and may be counterstained with other dyes, such as safranin, carbol fuchsin, neutral red. 革兰氏阴性菌（如蓝细菌）则会褪色，但可以被其他染料复染，如碱性藏红、品红或中性红。
Double staining involves the use of two stains;the second is called the counterstain. 复合染色过程利用了两种染料，后一种被称为复染剂。
It is often used with a green counterstain such a fast green or a blue counterstain, e.g. hematoxylin.See staining. 使用时常可与其绿色对应染料（固绿）或蓝色对应染料（苏木精）套染。
Labelling microcircumstance, the size of vessel opening diameter an d counterstain may also affect the result. 标记微环境，血管开口大小和复染可能影响标记结果。
They do not fade or damage specimens.Examples include fast green and the counterstain safranin.See also negative staining. 它们不会褪色或腐蚀标本，例如用番红固绿复合染料对标本进行永久复染。
RESULTS: Primarily cultured cells were colored with CD44 in-situ hybridization, kytoplasm as huffy and nucleus as blue by counterstain. 结果：原代细胞以CD44原位杂交显色，胞浆呈棕黄色，胞核经苏木精复染呈蓝色。
