Histology Stains

From Human Embryology


This page gives a general overview of some histological stains used to identify structures in embryo sections.

Histology Stains - Common Stains and Their Reactions
mucins - light blue
pale pink
bright red
colloid - pinkmuscle - red
Iron Haematoxylin
Van Gieson
muscle: yellow/browncartilage - pink
Verhoeff's Elastin
elastic fibres - black
Silver Impregnation
reticular fibres - black
Methyl Green
dark green
light green
light green
Nuclear Fast Red
Gomori's Trichrome
keratin - redmuscle - purple/red
Heidenhain's Azan
deep blue
muscle - red
Osmium Tetroxide
myelin, lipids - black
Alcian Blue
mucins, - blue
Periodic acid-Schiff (PAS)
mucins, glycogen, glycocalyx - magenta
Phosphotungstic Acid-Hematoxylin (PTAH)
muscle bands - blue
Masson's Trichrome
cartilage, mucins - blue or green; muscle - red
Luxol Fast Blue
myelin - blue
Aldehyde Fuchsin
elastic fibres, mast cells - deep purple
Light Green
light green
dark blue
nucleic acids, Nissl granules - dark blue
Romanowsky (e.g. Leishman's)
acidophils - red, basophils - blue, azurophilic - purple
Aldehyde Pararosanilin elastic fibres - purple

Acid Phosphatase

  • Stains lysosomes due to their acid phosphatase content.
  • Enzymatic activity of acid phosphatase (lysosomal enzyme) releases a precipitate of lead phosphate from solution. This is then converted to lead sulphide black deposit.

Alcian Blue

  • Stains mucopolysaccharides or glycosaminoglycans
  • cationic dye (positively charged molecule) for the demonstration of glycosaminoglycans.
  • binds anionic (negative) sites on the polysaccharide.
  • can be combined with H&E and VG staining methods.

Alizarine Blue

Alizarine Brilliant Blue R

Alizarin Red

  • Useful for identifying bone or other hight calcium structures.
  • Stains insoluble calcium cations
  • bright red stain
  • Other metals such as barium, aluminium, mercury and magnesium (dark red)


  • Stains nuclei a deep red and cytoplasm a pale red.

Best's Carmine

  • Stains glycogen granules red.
  • Periodic acid-Schiff is more commonly used and also colours glycogen red.

Cason's Trichrome

Stain developed by Cason (1950)[1] for muscle and collagen Aniline blue (methyl blue) colours collagen fibres.

  • red - nuclei
  • orange - erythrocytes
  • red - cytoplasm
  • blue - collagen

Stain constituents

  • Orange G
  • Acid fuchsin
  • Aniline blue (methyl blue)
  • Phosphotungstic acid
  • Distilled water

Congo Red

  • Congo red is water soluble, yielding a red colloidal solution; though its solubility is better in organic solvents, such as ethanol.
  • Previously used as a dye, but its properties (toxicity, colour change) means that it is no longer used for this purpose.
  • Has been used to detect amyloid in muscle and nerve fresh frozen sections.

Erythrosin Orange

  • Erythrosin B orange solution
  • dye for cytoplasm and connective
  • Dominici method for bone marrow biopsies.
  • Empirical Formula (Hill Notation) C20H8I4O5
  • Molecular Weight 835.89
  • CAS Number 15905-32-5

Golgi Method

  • (Golgi stain) A selective silver stain technique developed by Camillo Golgi (1843–1926) in 1873.
  • This historic technique allowed Santiago Ramón y Cajal (1852–1934) to interpret the structure of the central nervous system.
    • There are also a range of other silver staining techniques (see silver staining reticular fibres).

Gomori's Trichrome

  • Developed in 1950 by an American histologist George Gömöri (1904–1957).

Gram Stain

A bacterial staining procedure using crystal violet and pink safranin counterstain that generally divides bacteria into either gram-positive or gram-negative and useful for considering associated pharmacology. The procedure was named after Hans Christian Gram (1853 - 1938).

Gram-positive bacteria

  • Purple crystal violet stain is trapped by layer of peptidoglycan.
    • peptidoglycan forms outer layer of the cell.

Gram-negative bacteria

  • Outer membrane prevents stain from reaching peptidoglycan layer in the periplasm.
    • outer membrane is composed of four major components: lipopolysaccharide, phospholipids, beta-barrel proteins, and lipoproteins.
  • outer membrane then permeabilized.
  • Pink safranin counterstain is trapped by peptidoglycan layer.

Links: Medical Microbiology - Gram stain procedure

Haematoxylin and Eosin

One of the most common staining techniques in pathology and histology.

  • Acronym "H and E" stain. (H&E, HE)
  • UK - Haematoxylin, USA - Hematoxylin


  • UK - Haematoxylin, USA - Hematoxylin
  • Stains nuclei blue to dark-blue.
  • Stains the matrix of hyaline cartilage, myxomatous, and mucoid material pale blue.
  • Stains myelin weakly but is not noticeable if combined with eosin stain.
  • combined with Orange G (H & Or. G.) instead of eosin, specifically stains the granules of acidophilic cells of the adenohypophysis (anterior pituitary).


  • Stains cytoplasm pink to red; red blood cells are also bright red.
  • Common counterstain to hematoxylin.
  • Stain intensity varies with the formula as well as the fixative.

  • Eosin - (Greek, eos = dawn, rose-coloured) an acidic dye staining the basic cytoplasmic proteins pink.
  • Eosinophil - (Greek, + philein = to love) a type of blood cell with distinct cytoplasmic granules which stain pink with eosin.
  • Eosinophilic - having an affinity for eosin dye.

Heidenhain's Azan

  • Heidenhain (1915) introduced azocarmine G in place of the acid fuchsine in Mallory's trichrome method.
  • Staining is azocarmine G followed by a solution containing PTA, orange G and aniline blue.
  • Controlled the destaining to show different colours.
    • cell nuclei - dark red
    • collagen - blue
    • cytoplasm - variety of colours

Leishman's Stain

  • William Boog Leishman (1865 – 1926) was a Scottish pathologist.
  • Similar to other Romanowsky stains - Giemsa stain, Jenner's stain, and Wright's stain
  • Used to identify leucocytes, malaria parasites, and trypanosomas.
  • Methanol mixture of "polychromed" methylene blue (demethylated into various azures) and eosin.
    • dried precipitate known as "methylene azure" is sold as Leishman's Stain
  • Methanol also acts as fixative.
  • variations include Wrights Stain (America) and Giemsa and May-Grünwald stains in Germany and Europe.

Luxol Fast Blue

  • Myelin and phospholipids blue to green.
  • copper phthalocyanine dyes.
  • Counterstain with Cresyl violet (Nissl stain) to show neuron.
  • used as solutions in alcohol or other moderately polar liquids.

Mallory Trichrome Stain

(Mallory triple stain, Mallory aniline blue stain)

  • Stains connective tissue.
  • Mallory's trichrome method uses acid fuchsine followed by a solution containing PTA, orange G and aniline blue, provides dark red nuclei, orange erythrocytes, and blue collagen fibres, cartilage matrix and mucus.

Masson’s Trichrome Stain

Claude L. Pierre Masson (1880–1959)

  • Stains nuclei deep blue, skeletal and smooth muscles red, collagen and mucin blue.
  • Stains brain and spinal cord parenchymal tissue dusky pink to red.
  • Used to evaluate fibrosis
  • Striations in skeletal muscles also shows up much better in Masson’s trichrome than in hematoxylin and eosin stain.
    • Although called a trichrome, four dyes (hematoxylin, Biebrich scarlet, acid fuchsin, and analine blue) are utilized.

Masson-Goldner stain

Trichromic stain

  • black - (iron hematoxylin) stain nuclei
  • light green - mesenchyme green
  • orange - (azofuchsin) fibrin and parenchyma

Movat's stain

  • Connective tissue stain including cardiovascular tissue.
  • Pentachrome (five colour) stain:
    • Black - nuclei; elastic fibres
    • Yellow- collagen fibres; reticular fibres
    • Blue - ground substance; mucin
    • Bright red - fibrin
    • Red - muscle
  • Named after Henry Zoltan Movat who originally developed in 1955 and later modified by H. K. Russell in 1972.


(Mucin Stain, Al. carm.) Staining of acid mucopolysaccharides in tissue sections. Dye contains a large 2:1 dye-aluminum cationic complex, which is red. the mucicarmine solution is applied to sections after staining nuclei blue with a hemalum. the red dye-metal complex is attracted to anionic sites in the tissue (mucus, cartilage matrix, etc.) but it does not displace the nuclear stain. A yellow anionic dye such as picric acid or metanil yellow may optionally follow mucicarmine, as a cytoplasmic counterstain.[2]

  • Pink/Red - Mucin
  • Red - Capsule of Cryptococcus
  • Blue - Nuclei
  • Yellow - Other Tissue Components


  • Staining nucleic acids (ribosomes, RER, heterochromatin, nucleoli).
  • methylene blue, toluidine blue or cresyl violet is used.

Orange G

  • A general cytoplasmic stain similar to eosin.
  • Stains cytoplasm yellow or orange.
  • Combined with Haematoxylin or Periodic acid-Schiff to specifically stain granules of acidophilic cells of the adenohypophysis (anterior pituitary).

Osmium Tetroxide

  • has a great affinity for lipids and is chemically bound to the fat and as such acts as a fixative.
  • using osmium as a 'stain' makes use of the fact that osmium oxidises tissue fats and forms a black substance which is easily seen in the light microscope.
  • adipose tissue, adipose cells, myelin sheaths.

Papanicolaou stain

(Papanicolaou's stain, Pap stain) This histology technique was originally described in a publication by George Nikolas Papanicolaou in 1942.[3] A multichromatic (five dyes) staining histological technique has been used to stain many different human bodily fluids (CSF, semen, aspirations), used mainly in the "pap smear" histology. The technique has also been modified several ways (Bismarck brown Y deleted) from the original published technique.

  1. Haematoxylin - nuclear stain is used to stain cell nuclei.
  2. Orange G - stains keratin.
  3. Eosin Y - stains superficial epithelial squamous cells, nucleoli, cilia, and red blood cells.
  4. Light Green SF yellowish - stains the cytoplasm of non-keratinized squamous cells.
  5. Bismarck brown Y - stains nothing specifically, often omitted.

Periodic acid-Schiff


  • Stains glycogen, mucin, fungus, basement membrane and other substances.
  • Stain used to detect fungal organisms and cytoplasmic accumulation of glycogen.
  • Stains glycogen red, used in place of Best's Carmine.
  • Stains lysosomes granules red-purple, can be used in recognition of macrophages.

Periodic acid-Schiff / Orange G

  • Basophil cells - magenta
  • Acidophil cells - yellow
  • Red blood cells - yellow
  • Nuclei - blue/black
  • Chromophobes - pale blue/grey

Phloxine B


  • derivatives of eosin
  • used in the hematoxylin phloxine saffron (HPS) stain
  • stains paneth cell granules in Lendrum's phloxine-tartrazine method
  • used to demonstrate alcoholic hyaline
  • Formula - C20H2Br4Cl4Na2

PhosphoTungstic Acid Hematoxylin (PTAH)

  • Stains nucleus and cytoplasm detail and connective tissue fibers.
  • Stains collagen pink, fibrin blue, and striated muscle blue.
  • Historic stain used to show CNS reactive astrocytes now used immunochemistry for glial fibrillary acidic protein (GFAP).


(Picro-Mallory trichrome stain)

Regaud's Hematoxylin

  • Regaud's modification of iron hematoxylin.
  • Used to identify mitochondria by light microscopy.
  • material fixed in potassium dichromate and formalin and subsequently mordanted in dichromate.

Romanowsky Stain

There are a series of different histological stains that can be classified as Romanowsky stains.

  • Leishman's stain - commonly used version of Romanowsky stain for blood smears.
  • Giemsa stain
  • Jenner's stain
  • Wright's stain

Schmorl's Stain

File:Bone histology 003.jpg
Bone (Schmorl's Stain)
  • Stains canaliculi and lamellae in compact bone sections.
  • Stain has 2 colouring agents, ammoniacal thionin and aqueous saturated picric acid.
    • thionin precipitates within the lacunae and canaliculi (dark brown)
    • picric acid forms picrates in the bone matrix (brownish-yellow)
  • Named after Christian Georg Schmorl (1861 - 1932) a German pathologist.

Silver Stain

(Silver Impregnation)

There are a variety of specialised silver staining techniques.

  • Stains connective tissue collagen (type I) a grey/brown and the specialised reticular fibre collagen (type III) a dark black.
  • Silver deposits can be formed by 3 different reactions: argentaffin, argyrophil, and Ion-exchange.

Beilschowsky Silver

(Bielschowsky's silver staining)

  • Max Bielschowsky (1869 – 1940) was a Polish neuropathologist born in Breslau.
  • an improved method based upon Ramon y Cajal's historic method for selectively silver staining nerve fibres in neural tissue.

Methenamine Silver

(Jone's Methenamine Silver)

  • Stains the basement membrane of the glomerulus in the kidney.
  • A routine stain on kidney biopsies.
  • Periodic acid oxidizes the carbohydrate components of the basement membrane which produce aldehydes.
  • Released aldehydes reduce the silver to a visible metallic silver (black).

Sirius Red

  • collagen stain.
  • collagen is red on a pale yellow background.
  • polarized light microscopy - larger collagen fibers are bright yellow or orange, and thinner ones (including reticular fibres) are green.
  • Picro-sirius red method is an addition that prevents the loss of dye, that happens if the stained sections are washed in water.

Sudan Black

  • adipose tissue stain.
  • stain colours fat (lipid) droplets black.
  • several different Sudan dyes
  • Sudan III and Sudan IV (Scarlet R.) stain fat droplets red (as does Oil-red-O).


  • can be combined with Phloxine and Haem
    • tartrazine acts as a yellow counterstain for tissues stained red with phloxine
    • pancreatic islets - display pancreatic beta cells

Toluidine Blue

  • Stains nucleus blue and cytoplasm light blue.
  • A synthetic dye in the thiazins family.

Verhoeff-Van Gieson

  • Verhoeff-Van Gieson or elastic-Van Gieson (EVG) stain.
  • This is a combination of Verhoeff’s elastic stain which is a hematoxylin stain containing ferric chloride and Wright’s iodine solution and Van Gieson stain which contains acid fuchsin, picric acid, and hematoxylin.
  • Stains elastic fibers blue-black to black, collagen pale red, other tissue elements yellow, and nuclei blue to black.
  • Named after Ira Thompson Van Gieson (1866-1913) an American neurologist and neuropathologist and Frederick Herman Verhoeff (1874–1968) an American ophthalmic surgeon and pathologist.

Weigert's Elastic Tissue

  • Weigert's elastic tissue stain.
  • Elastic fibers purple or black.
  • combination of basic fuchsin, resorcin, ferric chloride, water and alcohol.


  • Wright's Blood Stain used on dried blood smears.
  • Nuclei blue or purple.
  • Granules - basophilic granules blue, acidophilic granules red, and neutrophilic granules reddish lilac.
  • Red blood corpuscles orange.
  • eosinates of polychromed methylene blue are dissolved in absolute methyl alcohol.
    • methyl alcohol acts as the fixative.

Whipf's Polychrome

A connective tissue staining technique.


See Histology Fixatives

Mounting Media

Mounting medium refers to the solution in which the specimen after staining is embedded on the slide under a cover glass. It may be liquid, gum or resinous, soluble in water, alcohol or other solvents. Some require sealing from the external atmosphere, while some are self-sealing media. (See also review.[4])

Historically, Canada balsam (Gurr) was the most common mounting media.[5]

Special mounting media have been developed for fluorescent dyes and microscopy.


Embedding (mountain) mediums are used in histology to enclose and support the specimen prior to sectioning and staining. Embedding also provides an easy long-term solution for long-term storing the tissue "blocks". Each embedding media has slightly differing properties, and needs to infiltrate the tissue, with paraffin and celloidin the two common embedding media.


Celloidin embedding - allows good morphological preservation though is difficult to remove, and may affect immunostaining.


Paraffin embedding - the most common historical technique and continues to be routinely used today in research and pathology laboratories, allows immunostaining to be performed, but preservation of fine cellular detail can vary.

  • mixture of straight chain or n-alkanes with a carbon chain length of between 20 and 40.
  • solid at room temperature (RT)
  • melts at temperatures up to 65°C or 70°C
    • can be supplied with melting points at different temperatures
    • at melting point tends to be slightly viscous, decreases as the temperature is increased (use about 2°C above melting point)
  • most common melting point for histological use 56°C–58°C (better infiltration of tissue at higher temperature)

Polyester Wax

Polyester wax embedding - has a low melting point (37°C), is organic solvent soluble, is water tolerant, and sections easily.


  1. Cason, (1950) Stain technology, vol.25, pp.225
  2. Kiernan, J.A., Carbohydrate Histochemistry Chapter 9, 75-92.
  3. <pubmed>17842594</pubmed>| Science
  4. Ravikumar S, Surekha R, Thavarajah R. Mounting media: An overview. J NTR Univ Health Sci (serial online) 2014;3, Suppl S1:1-8. Available from: http://www.jdrntruhs.org/text.asp?2014/3/5/1/128479
  5. <pubmed>17104830</pubmed>
  • Bancroft JD and Stevens A. Theory and practice of histological techniques. 3rd ed. Churchill Livingstone, 1990.

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