330000 Sigma-Aldrich

Rose bengal

Dye content 95 %

Synonym: 4,5,6,7-Tetrachloro-2′,4′,5′,7′-tetraiodofluorescein disodium salt, Acid Red 94, Bengal Rose B sodium salt, Rose Bengal sodium salt

  • CAS Number 632-69-9

  • Empirical Formula (Hill Notation) C20H2Cl4I4Na2O5

  • Molecular Weight 1017.64

  •  Beilstein/REAXYS Number 3645857

  •  EC Number 211-183-3

  •  MDL number MFCD00005043

  •  PubChem Substance ID 24859827

  •  NACRES NA.47



Related Categories Cell Biology, Hematology and Histology, Q-R, Stains & Dyes, A to Z, Stains and Dyes More...
form   solid
composition   Dye content, 95%
application(s)   hematology: suitable
  histology: suitable
λmax   549 nm
Featured Industry   Diagnostic Assay Manufacturing
storage temp.   room temp
SMILES string   [Na+].[Na+].[O-]C(=O)c1c(Cl)c(Cl)c(Cl)c(Cl)c1C2=C3C=C(I)C(=O)C(I)=C3Oc4c(I)c([O-])c(I)cc24
InChI   1S/C20H4Cl4I4O5.2Na/c21-10-8(9(20(31)32)11(22)13(24)12(10)23)7-3-1-5(25)16(29)14(27)18(3)33-19-4(7)2-6(26)17(30)15(19)28;;/h1-2,29H,(H,31,32);;/q;2*+1/p-2


General description

Rose Bengal is a red or rose color dye and is anionic in nature. It is a 4,5,6,7-tetrachloro 2′,4′,5′,7′-tetraiodo derivative of fluorescein. It is widely used to detect damage to the ocular surface epithelium in ocular surface diseases such as dry eye and herpetic keratitis. Rose Bengal has mild antiviral potency.

Rose Bengal is used to stain dead and degenerating cells and mucus.


Rose Bengal has been used to evaluate acrosome integrity. It has also been used to initiate photothrombotic occlusion in blood.


1, 5 g in glass bottle

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

Please Enter a Lot Number

Certificate of Origin (COO)

Please Enter a Lot Number

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.
How do I get lot-specific information or a Certificate of Analysis?
The lot specific COA document can be found by entering the lot number above under the "Documents" section.
How do I find price and availability?
There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote. USA customers: 1-800-325-3010 or view local office numbers.
What is the Department of Transportation shipping information for this product?
Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.
What is the solubility of Rose Bengal, Product 330000?
According to The Sigma-Aldrich Handbook of Stains, Dyes and Indicators, Rose Bengal is soluble in water at 100 mg/mL, ethanol at 30 mg/mL and 2-methoxyethanol at 60 mg/mL. Conn's Biological Stains (10th Edition) states Rose Bengal has a solubility of 36% in water and 8% in ethanol.
What types of applications can Product 330000, Rose bengal be used for?
According to the literature, Rose bengal has been used in a used in neutrophil adherence test and as a generator of singlet oxygen when exposed to laser energy. See: McKinnon, J. , Expt. Med., 164, 1864, (1986) and Gamble and Vadas, Science, 242, 97, (1988).
What is the quantum yield of Rose bengal, Product 330000?
According to the literature, the quantum yield of Rose bengal is 0.11. See: Seybold, P.G., et al., Calorimetric, photometric and lifetime determinations of fluorescence yields of fluorescein dyes, Photochem. Photobiol., 9, 229-242 (1969).
My question is not addressed here, how can I contact Technical Service for assistance?
Ask a Scientist here.
Show more questions
Protocols & Articles


HPLC Analysis of Synthetic Food Dyes on Ascentis® Express C18

From our library of Articles, Sigma-Aldrich presents HPLC Analysis of Synthetic Food Dyes on Ascentis® Express C18
Keywords: Chromatography, High performance liquid chromatography

Related Content

Tissue Diagnostics

Discover our newly expanded and even more comprehensive product range for your tissue diagnostics workflow. We are dedicated to covering all your requirements and delivering quality in the fields of ...
Keywords: Cell biology, Hematology

Peer-Reviewed Papers


Related Products

Technical Service:

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

Bulk Ordering & Pricing:

Need larger quantities for your development, manufacturing or research applications?