3-Indoxyl caprylate is a chemiluminescent substrate that is used in the detection of bacteria. It has been shown to be a very sensitive and selective fluorogenic substrate for the detection of bacterial activity, which can be used with an appropriate enzyme reaction. 3-Indoxyl caprylate has also been shown to be a potent quencher of bioluminescence, and can be used as a chromogenic substrate in diagnostic assays. 3-Indoxyl caprylate is often used as a culture media supplement or food additive to enhance its growth properties.