An indol-3-yl carboxylic acid that is propionic acid substituted by a 1H-indol-3-yl group at position 3. ChEBI: 3-(1H-indol-3-yl)propanoic acid is an indol-3-yl carboxylic acid that is propionic acid substituted by a 1H-indol-3-yl group at position 3. It has a role as an auxin, a human metabolite and a plant metabolite. It is functionally related to a propionic acid. It is a conjugate acid of a 3-(1H-indol-3-yl)propanoate.