Kethoxal (3-ethoxy-1,1-dihydroxy-2-butanone) is an organic compound that has antiviral and anaplasmosis properties.

[1][3] It also forms a stable covalent adduct with guanine, which makes it useful for nucleic acid structure determination.

[4] Kethoxal, as with other 1,2-dicarbonyl compounds,[5] reacts with nucleic acids.

In whole RNA, it reacts preferentially with guanine residues that are not involved in hydrogen-bonding.

The binding is reversible, which allows the kethoxal to be removed and the original RNA recovered.