Ethylenediaminetetraacetic acid (EDTA) is an aminopolycarboxylic acid and a hexadentate ligand. It chelates with metal ions, especially with cations to form an octahedral complex. Ethylenediaminetetraacetic acid disodium salt (EDTA) is a blood anticoagulant and contributes to the pathogenesis of pseudothrombocytopenia. It chelates with calcium in the blood and inhibits clotting and is routinely used in haematological tests. It enhances the antibacterial activity of lysozyme. EDTA used in chelation therapy chelates with calcium and favors dilation of artery, solubilisation of atheromatous plaques in atherosclerotic vascular disease. EDTA chelation therapy may also protect from oxidative damage during blood and lipid peroxidation in liver fibrosis.

Chelator of divalent cations. Inhibits enzymes, such as metalloproteases, that require divalent cations for activity.

Ethylenediaminetetraacetic acid disodium salt dihydrate has been in seed germination trials of plant species and in protein extraction from Moss, Physcomitrella paten. It has also been used in lysis and vacuole buffer for the isolation of vacuoles from Petunia petals.