6-Chloro-3-indoxyl-beta-D-galactopyranoside is a chromogenic substrate for beta-galactosidase that yields a salmon or rose-coloured precipitate and hence is also known as Salmon-Gal

It can be used in conjunction with isopropyl-beta-D-thiogalactopyranoside as an alternative to the chromogenic substrate 5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside for detection of beta-galactosidase activity in bacterial colonies in colorimetric assays