A fluorescent stain which has a function of clarifying the shape of the surface of the gastrointestinal lumen in the visible light wavelength region, and simultaneously, emitting fluorescence by being excited by light of a specific wavelength, and which is also biologically safe and is suitable for endoscopic observation, is provided. A histofluorescent stain composition for endoscopy, containing a compound represented by the following Formula (1): wherein R.sup.1 represents a hydrogen atom or a hydroxyl group; R.sup.3 represents a phenyl group or methyl group, to which R.sup.2c is bound; one to three of R.sup.2a, R.sup.2b and R.sup.2c represent --SO.sub.3M (wherein M represents an alkali metal atom or an alkaline earth metal atom), or --SO.sub.3NH.sub.4, and when one represents --SO.sub.3.sup.-, the others represent hydrogen atoms is provided.