Lactophenol Cotton Blue (LPCB).

For the staining and microscopic identification of fungi.


  • Cotton blue (Aniline blue) 0.05 g
  • Phenol crystals (C6H5O4) 20 g
  • Glycerol 40 mL
  • Lactic acid (CH3CHOH COOH) 20 mL
  • Distilled water 20 mL


This stain is prepared over two days.

On the first day, dissolve the Cotton blue in the distilled water. Leave overnight to eliminate insoluble dye.

On the second day, wearing gloves add the phenol crystals to the lactic acid in a glass beaker. place on magnetic stirrer until the phenol is dissolved.

Add the glycerol.

Filter the Cotton blue and distilled water solution into the phenol/glycerol/lactic acid solution. Mix and store at room temperature.