Gram-bacteria staining - outstanding solutions

Gram staining is a technique in bacteriology, which enables the differentiation of bacteria into gram-positive and gram-negative groups. In this method, Gram-positive bacterial cells retain their blue-violet colour, whereas Gram-negative bacterial cells appear orange-pink when counterstained.

Various solutions are needed for this multi-step staining process, including aniline dye and iodine solution, as well as safranine orange or carbol fuchsin counterstains. Not only do we offer all required solutions for Gram’s method, but also ready-to-use sets and kits that guarantee easy handling and reliable staining results. Among these is our phenol-free kit, which increases user safety as it prevents the release of toxic phenol vapour. Since all of our Gram-staining solutions and kits are IVDs and CE certified, they can be used in clinical diagnostics as well as industrial quality control.

Product range

  • Gram-colour kit, includes all required solutions in convenient pack
  • Gram-colour modified, phenol-free is a staining set for staining microorganisms

Aniline dyes in the cell tissue of microorganisms form a red dye-iodine complex when exposed to iodine. Sodium hydrogen carbonate enhances the formation of this complex further still. In Gram-positive microorganisms the dye-iodine complex cannot be subsequently dissolved from the cells by decolourising agents such as alcohol or acetone. The cell remains dark blue in colour. In Gram-negative microorganisms the dye-iodine complex is dissolved and the cell turns red as a result of counterstaining. Gram-colour modified, phenol-free is an IVD / CE product. The package is sufficient for 65 – 70 applications.

We offer Gram individual solutions, including Gram’s crystal violet solution, Gram’s safranine solution, Gram’s decolourisation solution, Lugol’s solution and Lugol’s solution stabilized with PVP.

Merck Millipore

Tel: 08600 63725

Fax: 0860 522329

[email protected]


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