Indole-3-pyruvic acid is an endogenous metabolite of tryptophan and intermediate in the biosynthesis of the major auxin hormone, indole-3-acetic acid (IAA; ), in plants. Indole-3-pyruvic acid (50 and 250 µM) activates the aryl hydrocarbon receptor (AhR) in a reporter assay. It reduces UVB-induced cytotoxicity and the levels of COX-2 in HaCaT keratinocytes. Topical administration of indole-3-pyruvic acid (100 µmol) reduces the severity of UVB-induced damage in mouse skin. Dietary administration of indole-3-pyruvic acid (0.1%) reduces diarrhea, colonic inflammation, and the colonic expression of Il1b, Ifng, Tnfa, and Il12b in a mouse model of T cell-mediated colitis. It increases the time spent in the open arms of the elevated plus maze in mice when administered at a dose of 100 mg/kg. It also reverses the anxiogenic effect of caffeine and 3-hydroxy kynurenine, but not pentylenetetrazole or phenylethylamine, in the elevated plus maze in mice.