Boric acid also called hydrogen borate boracic acid orthoboric acid and acidum boricum is a weak monobasic Lewis acid of boron often used as an antiseptic insecticide flame retardant neutron absorber or precursor to other chemical compounds. It has the chemical formula H3BO3 (sometimes written B(OH)3) and exists in the form of colorless crystals or a white powder that dissolves in water. When occurring as a mineral it is called sassolite.

For R&D use onlynot for drug household or other uses.