The asymmetric unit of the title compound (systematic name: 3,3,8,8-tetramethyl-1,4,6,9-tetraoxa-λ4-boraspiro[4.4]nonane-2,7-dione tetrahydrate), C8H12BO6·4H2O, consists of half a bis(2-methyllactato)borate molecule and two water molecules of solvation. In the crystal, O—H...O hydrogen bonds link the components into a three-dimensional network.
