4-aminobenzoic acid is an organic acid with UV-absorbing and antifibrotic properties. When exposed to light, 4-aminobenzoic acid absorbs UV light and releases excess energy through a photochemical reaction, which may cause DNA damage.4-aminobenzoic acid also increases oxygen uptake at the tissue level and may enhance monoamine oxidase (MAO) activity to promote serotonin degradation, which in excess may lead to fibrotic Changes.

4-Aminohippuric Acid is the glycine amide of 4-aminobenzoic acid. Its sodium salt is used as a diagnostic aid to measure effective renal plasma flow (ERPF) and excretory capacity.