To elucidate the molecular mechanism mediating the inactivated effect of DMV neurons on fat absorption, we performed an activity-based protein profiling strategy, using Puerarin as a “bait”. The Puerarin-tag probe was synthesized with a photoreactive tag to enrich and visualize target proteins via a photoaffinity chemistry reaction. We verified that probe-tagged Puerarin retains the same effects of increasing fecal lipid excretion as non-tagged Puerarin. Probe-tagged Puerarin was added to the freshly isolated brainstem sample, and 10 doses of non-tagged Puerarin was used as a competitor of probe-tagged Puerarin. Following the photoaffinity reaction, targeted proteins were subsequently assessed by liquid chromatography tandem mass spectrometry (LC-MS).