The reduction of vanadium(V) and molybdenum(VI) has been carried out in aqueous HCl by various hydroxy-containing compounds such as hexoses (d-glucose, d-fructose, and d-galactose), pentoses (d-ribose and d-xylose), glycols [ethylene glycol, di(ethylene glycol), tri(ethylene glycol), tetra(ethylene glycol), and poly(ethylene glycol)], and mono-, di-, and tri-ethanolamines. The relative reducing abilities of these compounds are compared with those of l-ascorbic acid and l-cysteine. The trend is similar to that reported earlier for chromium(VI) reduction. Based on this study it is concluded that hydroxy-containing compounds play important roles in complexation and reduction of metal ions. © 1995.