All Photos(2)



Toluidine Blue O

certified by the Biological Stain Commission

Tolonium chloride, Methylene Blue T50 or T extra, Basic Blue 17, Blutene chloride
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
Colour Index Number:
EC Number:
MDL number:
PubChem Substance ID:

Quality Level


certified by the Biological Stain Commission




Dye content, 80%


626 nm

ε (extinction coefficient)

≥13000 at 241-247 nm in H2O
≥28000 at 287-293 nm in H2O
≥40000 at 625-635 nm in H2O


diagnostic assay manufacturing

storage temp.

room temp

SMILES string




InChI key


Looking for similar products? Visit Product Comparison Guide

General description

A metachromatic dye suitable for a wide variety of histological staining procedures.


Toluidine Blue O along with light-emitting diode has been used as a photosensitizer to control in vitro biofilms and to kill gram-negative bacteria.


5, 25 g in glass bottle

Biochem/physiol Actions

Toluidine Blue O (TBO) is a thiazine dye of the quinone-imine family and is cationic in nature. It has been employed in polychromatic staining of paraffin embedded plant cell walls. TBO can be removed from its aqueous solution by using an effective adsorbent, clinoptilolite. TBO and fixed output laboratory laser light source are used together to destroy variety of oral bacteria associated with dental caries. This metachromatic nuclear stain is often used in place of thionin or methylene blue. It also serves as a component of a tribasic stain along with Malachite Greenand Basic Fuchsin.


Certified for use as a metachromatic stain for mast cells and cartilage using the Churukian-Schenk method and the method of Nocht on paraffin sections.

Storage Class Code

13 - Non Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Certificate of Origin

Photosensitization of in vitro biofilms by toluidine blue O combined with a light-emitting diode.
Zanin IC
European Journal of Oral Sciences, 114(1), 64-69 (2006)
Anaīs Noblanc et al.
Antioxidants (Basel, Switzerland), 9(2) (2020-02-15)
There is growing evidence that the quality of spermatozoa decreases with age and that children of older fathers have a higher incidence of birth defects and genetic mutations. The free radical theory of aging proposes that changes with aging are
The Effect of Variable Energy Input from a Novel Light Source on the Photoactivated Bactericidal Action of Toluidine Blue O on Streptococcus mutans
Williams J A
Caries Research, 37, 190?193-190?193 (2003)
Polychromatic staining of plant cell walls by toluidine blue O
Brien T P O
Protoplasma, 59(2), 368- 373 (1964)
The adsorption kinetics and removal of cationic dye, Toluidine Blue O, from aqueous solution with Turkish zeolite
Alpat S K
Journal of Hazardous Materials, 151(1), 213-220 (2008)

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service