1-Naphthyl 2-acetamido-2-deoxy-b-D-galactopyranoside (1NADG) is a fluorogenic substrate that reacts with an enzyme to produce light. It is used in diagnostic tests for the detection of bacteria, and can be used as a chromogenic substrate in biochemical assays. 1NADG has also been shown to be useful in staining bacterial cells grown on agar plates. Additionally, this compound is used as a bioluminescent probe for detecting bacteria with luciferase activity.