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Ethidium Homodimer III (EthD-III)

A red fluorescent dead cell stain for bacteria and mammalian cells that is brighter than Ethidium Homodimer I.

Product Attributes

Probe cellular localization

Nucleus & cytoplasm

Assay type/options

Real-time imaging

Cell permeability

Membrane impermeant

Apoptosis/viability marker

Dead cell stain




279, 532/625 nm (with DNA)

Storage Conditions

Store at 2 to 8 °C, Protect from light

Molecular weight


Note: Due to operating restrictions related to our COVID-19 response, primary antibody conjugates of R-PE, APC, PerCP, HRP, or AP are temporarily unavailable. All other antibody options are still available. We apologize for the inconvenience. Please see our easy-to-use Mix-n-Stain™ Antibody Labeling Kits for labeling antibodies with R-PE, APC, tandem dyes, and enzymes.
Catalog #
1 mg
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Product Description

Ethidium Homodimer III, also known as EthD-III, is a red fluorescent dead cell stain for bacteria and mammalian cells. It is a cell membrane-impermeant nucleic acid dye that stains only dead cells with damaged cell membranes. Ethidium Homodimer III was developed by Biotium as a superior alternative to Ethidium Homodimer I. The absorption and emission spectra are similar, but EthD-III is 45% brighter.

  • Dead cell-specific DNA stain
  • Can be used in mammalian, yeast, and bacteria cells
  • 45% brighter than Ethidium Homodimer I
  • Provided as a red solid

Ethidium Homodimer III is membrane impermeant and useful for selectively staining dead cells with damaged plasma membranes. It also is a component of several combination viability assay kits for detecting both live and dead cells in the same population, such as our Viability/Cytotoxicity Assay Kit for Animal Cells (Cat. No 30002) and our Viability/Cytotoxicity Assay Kit for Bacteria (Cat. No. 30027).

We also offer Ethidium Homodimer III, 1 mM solution in DMSO (catalog no. 40051).

EthD-III is dead cell specific in all cell types, including mammalian cells, bacteria and yeast. See our Cellular Stains Table for more information on how our dyes stain various organisms.



1. Mol Cancer Res 6, 965 (2008).
2. J Pharmacol Exp Therap 332, 738 (2010).


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