Fast Green FCF

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.

Fast Green FCF is poorly absorbed by the intestines. Its use as a food dye is prohibited in European Union and some other countries. It can be used for tinned green peas and other vegetables, jellies, sauces, fish, desserts, and dry bakery mixes at level of up to 100 mg/kg. 

Its risk phrases are R36, R37, and R38.