Phosphotungstic acid-Orange G solutions are histological and cytological stains available in four different concentrations. These solutions combine phosphotungstic acid, a strong oxidizing agent, with Orange G, a synthetic azo dye. The four variants differ in the composition of phosphotungstic acid (2 g to 50 g) and Orange G (2 g to 20 g).

The use of these solutions makes it possible to study cellular details and morphological differences between different cell types and tissues. They are commonly used to stain cellular structures such as nuclei, cytoplasm, and extracellular matrix. Phosphotungstic acid orange G solutions are often used in combination with other dyes or reagents to selectively stain different cellular components and tissue structures and visualize them under the microscope.

The different concentrations of phosphotungstic acid orange G solutions allow users to select the optimal staining intensity and specificity for their particular requirements.