Methylene blue

Other Names: 
Methylthionium chloride
Methylene blue is an oxidation-reduction agent which reduces ferric iron in oxidized hemoglobin to the ferrous form at low concentrations 1% or less (at high concentrations it is itself a potent oxidizer).
Used in the treatment of methemaglobinemia following exposure to oxidizing agents and nitrate accumulating plants; Analine derivatives, Phenacetin (Acetanilide), Benzocaine, Chloates, Hydrazine, Dapsone, Nitrates, Nitrites, Nitrobenzenes, Cresol, Duron, Gluthetimide, Cetacaine, Mercaptan, Napthalene, Nitric Oxide, Nitroglycerin, Propylene glycol dinitrate, Nitrofurantoin, Nitrotolulenes, Promiquine, Quinine, Pigweed (Amaranthus), Galenia groundcover (Galenia), Ragweeds (Ambrosia), Canada thistle (Cirsium), Cudweeds (Gnaphalium), Sunflower (Helianthus), Milk thistle (Silybum), Golden eyes (Viguiera), Sorghum (Poaceae), Sage (Salvia), Lambsquarter and Goosefoot (Chenopodium).