Congo Red Stock Solution II, consisting of ethanol, distilled water, sodium chloride and Congo Red, is an important component in the histological field, especially when using the Congo Red staining kit according to Hertie.

The chemical components of the solution, especially Congo red (C.I. 22120), an anion dye, interact specifically with certain tissue components. Congo red binds selectively to amyloid fibrils, which is useful in the diagnosis of amyloidosis or Alzheimer's disease.

The properties of Congo red, including its ability to switch between red and blue hues, are highly dependent on the environment into which it is introduced. Ethanol and distilled aqua serve as solvents in this regard, while sodium chloride contributes to the ionic strength of the solution.

The main result of using Congo Red Stock Solution II in histology is the identification and visualization of amyloid deposits in tissue specimens. This information contributes significantly to the diagnosis and treatment of amyloidosis.