3,4-dihydroxybenzoic acid is a kind of antibacterial components that can play a certain role in escherichia coli, pseudomonas aeruginosa, dysentery bacillus, Bacillus subtilis and Staphylococcus aureus, etc. It comes naturally from the leaves of fern, Holly and other plants as well as nuts and vegetables. The 3,4-dihydroxybenzoic acid that we see in the industrial market is generally a white to brown crystalline powder in appearance, and its color will change if it is placed in the air. The 3,4-dihydroxybenzoic acid in boiling water breaks down and releases carbon dioxide. Aqueous solutions of 3,4-dihydroxybenzoic acid turn green in the presence of ferric chloride and red in the presence of sodium bicarbonate.
3,4-dihydroxybenzoic acid is common in medicine, food, chemical and other fields. It is the precursor of synthesis of complex molecules such as anthocyanin and has a variety of biological activities. From the medical point of view, it is the raw material of a variety of drugs, which is of great help to maintain our health.