AFB Ziehl–Neelsen Carbol Fuchsin is formulated for use as the primary stain in the Ziehl–Neelsen acid-fast staining procedure. When applied with heat, the stain penetrates the lipid-rich cell walls of acid-fast organisms, producing an intense red coloration that resists decolorization with acid-alcohol. This allows clear differentiation of acid-fast bacteria from non–acid-fast material following counterstaining. Suitable for routine use in clinical, veterinary, and research laboratories, this reagent is compatible with standard Ziehl–Neelsen protocols and manual staining procedures. The formulation supports consistent staining performance and reliable microbiology results.