Used in histology and microbiology as a staining reagent, particularly in Gram staining to differentiate bacterial types. The solution helps in the visualization of cell morphology under the microscope by selectively coloring Gram-positive bacteria, which retain the crystal violet-iodine complex, appearing purple. Ammonium oxalate acts as a mordant and stabilizer, enhancing the binding of the dye to cellular components. Also employed in some antifungal treatments and as a topical antiseptic in veterinary applications due to its antimicrobial properties. Commonly used in agar media preparation to inhibit contaminant growth while allowing selective culture of desired organisms.