Lugol′s solution (diluted iodine-potassium iodide solution)

for the Gram staining method

Iodine-potassium iodide solution

storage conditions

Store at +15°C to +25°C.

Quality Level




for in vitro diagnostic use


hematology: suitable
histology: suitable


3.5 (20 °C in H2O)


100 °C/1013 hPa


1.01 g/cm3 at 20 °C

Featured Industry

Clinical Testing
Diagnostic Assay Manufacturing

storage temp.


General description

In bacteriology, the Gram staining allows a fast differentiation of bacteria in Gram-positive and Gram-negative. The mureine structure of the bacteria walls is the basis of the color affinity. Bacteria will be stained with Gram′s crystal violet solution - an aniline dye - in the first step. After the treatment with Gram′s iod solution (Lugol’s solution), a dye-iod complex will form. During the decolorizing step, this complex stays in the multilayer mureine structures of the Gram-positive bacteria and they will appear blue. Gram-negative bacteria have a monolayer mureine structure only, the dye-iod complex does not stay bound to the cellwall, they will be decolorized . Gram-negative bacteria will be counterstained by Gram′s safranin solution and appear orange. A 500 mL PE-bottle of Gram′s Lugol′s solution is sufficient for staining up to 250 slides. Lugol’s solution is also a part of the Gram-color stain set. It is an IVD & CE product.

Certificate of Analysis

Certificate of Origin

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

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon


Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.