A solution containing a dye (e.g., iodine, indigo carmine) intended to be used during endoscopic procedures (e.g., gastroscopy, colposcopy) to stain epithelial surfaces to help screen for mucosal lesions [e.g., oesophageal squamous dysplasia, gastrointestinal polyps, adenomas, cervical carcinoma]. It is typically applied onto the epithelium whereby lesions are observed by visualization of stained or unstained tissue. After application, this device cannot be reused.