tolonium

Tolonium chloride (INN, also known as toluidine blue or TBO) is a phenothiazine that has been used as a hemostatic, a biological stain, and a dye for wool and silk. Tolonium chloride has also been used as a diagnostic aid for oral and gastric neoplasms and in the identification of the parathyroid gland in thyroid surgery. Toluidine blue has high affinity for acidic tissue components, thereby staining tissues rich in DNA and RNA. It has found wide applications both as vital staining in living tissues and as a special stain owing to its metachromatic property. Toluidine blue has been used in vivo to identify dysplasia and carcinoma of the oral cavity. — NCATS