Methylene Blue is a basic aniline dye with a chemical formula of C16H18N3SCl.3H2O. Methylene Blue forms a deep blue solution when dissolved in water, although in solid form it appears as a dark green odourless powder. It has many uses medically, in biology and in chemistry. Methylene Blue is a different substance to Methyl Blue or Methyl Violet and should not be confused with these.
Amongst its uses are as a bacterial stain and as an antidote for Cyanide poisoning. It is also used in dentistry in the treatment of lesions in the mucous membranes of the mouth. In microscopy, Methylene Blue is used as a stain to colour bacteria before examination. As it provides only temporary staining, Methylene Blue is used to examine RNA or DNA under the microscope.
Methylene Blue is widely used in analytical chemistry as a Redox Indicator and as a photosensitiser. It is also used by chemists to detect oxidizing agents. In medicine, it is used as a treatment for various illnesses and disorders from schizophrenia , kidney stones and herpes infections. In the late 1800's, Methylene Blue was used as an anti-malarial treatment but became unpopular as its side effects include turning the white of the eyes blue, a condition known as 'sclera' and also turning the urine green.
Keepers of fish aquariums use Methylene Blue to protect newly laid fish eggs from fungal or bacterial infection. Methylene Blue is also used to provide a 'medicated fish bath' for the treatment of sick or injured fish and for the treatment of Ammonia, Nitrite or Cyanide poisoning.
When handling any chemical material care should be taken. When handling Methylene Blue always read the MSDS (Material Safety Data Sheet) supplied with the product before working with or handling Methylene Blue. Wear appropriate personal protective equipment (PPE) when working with Methylene Blue including protective clothing, footwear, compatible safety gloves and approved eye protection.
Methylene Blue is classified as Harmful if swallowed and may be Harmful if inhaled and in contact with skin. Methylene Blue causes severe eye irritation which can lead to chemical conjunctivitis and corneal damage, so safety glasses should always be worn to prevent accidental splashes coming into contact with the eyes.