New methylene blue

is an organic compound of the thiazine class of heterocycles. It is used as a stain and as an antimicrobial agent. It is classified as an azine dye, and the chromophore is a cation, the anion is often unspecified.

Applications
NMB is a staining agent used in diagnostic cytopathology and histopathology, typically for staining immature red blood cells. It is a supravital stain. It is closely related to methylene blue, an older stain in wide use.

Safety
New methylene blue is toxic. Skin contact or inhalation should be avoided.