[1] Synthetic quinolone antibiotics were discovered by George Lesher and coworkers as a byproduct of chloroquine manufacture in the 1960s;[2] nalidixic acid itself was used clinically, starting in 1967.

It has historically been used for treating urinary tract infections, caused, for example, by Escherichia coli, Proteus, Shigella, Enterobacter, and Klebsiella.

Nalidixic acid and related antibiotics inhibit a subunit of DNA gyrase and topoisomerase IV and induce formation of cleavage complexes.

[10][11][12] In case of overdose the patient experiences headache, visual disturbances, balance disorders, mental confusion, metabolic acidosis and seizures.

[13] Aeromonas hydrophila, Clostridium and Haemophilus are generally susceptible to nalidixic acid, while other bacteria such as Bifidobacteria, Lactobacillus, Pseudomonas and Staphylococcus are resistant.