固绿FCF是一种海绿色的三芳基甲烷食用色素。

固绿FCF可以作为马松三色染色法(Masson's trichrome stain)的亮绿SF淡黄的代替品，其颜色更明快且不容易褪色。它也在酸萃取DNA之后在堿环境下用作组蛋白的定量染色剂。在电泳中用作蛋白质染色剂。最大吸收量是625nm。

内脏很难吸收固绿FCF。 虽然它可以用来染蔬菜、果冻、酱汁和其他很多食物，欧盟和一些其他国家依然禁止使用固绿FCF作为食物染色剂。 在美国其使用也受到了限制。日本厚生省则将之分类为天然存在的添加物。

Fast Green FCF, also called Food green 3, FD&C Green No. 3, Green 1724, Solid Green FCF, and C.I. 42053, is a sea green triarylmethane food dye. Its E number is E143.

Fast Green FCF is recommended as a replacement of Light Green SF yellowish in Masson's trichrome, as its color is more brilliant and less likely to fade. It is used as a quantitative stain for histones at alkaline pH after acid extraction of DNA. It is also used as a protein stain in electrophoresis. Its absorption maximum is at 625 nm.