2,4-Dihydroxybenzoic acid

2,4-Dihydroxybenzoic acid (β-resorcylic acid) is a dihydroxybenzoic acid.

As a resorcylic acid, it is one of the three isomeric crystalline acids that are both carboxyl derivatives of resorcinol and dihydroxy derivatives of benzoic acid. Synthesis from resorcinol is via the Kolbe-Schmitt reaction.

It is a degradation product of cyanidin glycosides from tart cherries in cell cultures. It is also a metabolite found in human plasma after cranberry juice consumption.