3,5-Dinitrosalicylic acid (DNS or DNSA, IUPAC name 2-hydroxy-3,5-dinitrobenzoic acid) is an aromatic compound that reacts with reducing sugars and other reducing molecules to form 3-amino-5-nitrosalicylic acid, which strongly absorbs light at 540 nm.

It was first introduced as a method to detect reducing substances in urine by James B. Sumner[2] and has since been widely used, for example, for quantifying carbohydrate levels in blood.

However, enzymatic methods are usually preferred due to DNS's lack of specificity.

[4] 3,5-Dinitrosalicylic acid can be prepared by the nitration of salicylic acid.

This article about an aromatic compound is a stub.