The molecular formula C₇H₆O₄ may refer to:

• Dihydroxybenzoic acids, a type of phenolic acids
  • 2,3-Dihydroxybenzoic acid (2-pyrocatechuic acid or hypogallic acid)
  • 2,4-Dihydroxybenzoic acid (β-resorcylic acid)
  • 2,5-Dihydroxybenzoic acid (gentisic acid)
  • 2,6-Dihydroxybenzoic acid (γ-resorcylic acid)
  • 3,4-Dihydroxybenzoic acid (protocatechuic acid)
  • 3,5-Dihydroxybenzoic acid (α-resorcylic acid)
• Patulin, a mycotoxin produced by a variety of molds