Fuchsin-Chrysoidin-Astrablau (FCA) according to Etzold is a staining method mainly used in botany to study plant cells and tissues. The stain consists of a mixture of neufuchsin, chrysoidin G, astra blue and acetic acid. This combination of dyes allows visualization and differentiation of various cell structures and tissue components in plant preparations.

Neufuchsin stains nuclei and chromoplasts red, chrysoidin G stains mitochondria and plastids yellow to orange, and astrablau stains cell walls, vacuolar membranes and other cell structures blue. Acetic acid is used as a solvent and buffer to stabilize the pH of the stain.

Although the primary application of FCA staining is in botany, it is possible that it could be used in other research areas if specific staining of these cell structures is required.