Tissue staining during endoscopy (chromoendoscopy) is a technique used to study the fine details of the mucosa throughout the gastrointestinal tract. Each stain has a few specific clinical applications. Dyes can be classified into three categories: absorptive (vital) stains, topical contrast stains and reactive stains. Endoscopic tatooing is a different technique where a specific site in the gastro- intestinal tract is labelled by an intramural injection of a carbon ink suspension for future identification. The objective of this article is to review the multiple clinical applications of tissue staining during endoscopy, explain the different stain’s mechanism of action, and elaborate on the specific techniques of stain preparation and appli- cation.

        Key words: chromoendoscopy, classification of dyes, Lugol solution, Kongo red, methylene blue, toluidine blue,India ink