Methylene Blue Solution has been optimized in our research laboratories to give outstanding results when used in various procedures such as the Ziehl-Neelsen, Fite’s, and Gram stain. The stain is also suggested for use in staining a variety of bacteria (Corynebacterium diphtheria, Haemophilus influenzae, Neisseria, etc.) and leukocytes. This reagent produces dark blue nuclei with very light blue cytoplasm.