Masson's trichrome is a stain that highlights collagen fibers. This method is very popular and is used in histology to differentiate collagen and muscle fibers on tissue sections. It is particularly used in the study of pathologies of the heart (infarction), liver (cirrhosis), kidney (glomerular fibrosis).

Most recipes stain keratin and muscle fibers in red, collagen and bone in blue or green, cytoplasm in light red or pink, and nuclei in black.

The technique called "Masson's trichrome" is applied to sections of animal tissues, and involves 3 successive stainings:

1) Staining of the nuclei with Mayer's hemalun or Hematoxylin by Harris

2) Staining of the cytoplasm by a precise mixture of acid fuchsin and red culvert (which are acid dyes).

3) Elective staining of collagen by light green (sometimes replaced by aniline blue)