Kynurenic acid was discovered in 1853 by the German chemist Justus von Liebig in dog urine, which it was apparently named after.

[2] KYNA has been proposed to act on five targets: High levels of kynurenic acid have been identified in patients with tick-borne encephalitis,[9] schizophrenia and HIV-related illnesses.

Kynurenic acid acts in the brain as a glycine-site NMDAr antagonist, key in glutamatergic neurotransmission system, which is thought to be involved in the pathophysiology and pathogenesis of schizophrenia.

[13] High levels of kynurenic acid have been identified in human urine in certain metabolic disorders, such as marked pyridoxine deficiency and deficiency/absence of kynureninase.

[15] Some researchers have posited that the increased levels found in cases of neurological degradation is due to a failed attempt to protect the cells.