Effects of the steroids, norethindrone and mestranol on stomatal resistance, leaf water potential, leaf osmotic potential, and uptake of K+, Ca2+ and Fe2+ were determined. Leaves from 20 day old winter wheat plants (T. aestivum L. em. Thell.), grown in nutrient solution for 30 days with the steroids, were used. Stomatal resistance increased with increasing concentration of steroids. Even though steroid-treated plants had lower water potentials and osmotic potentials compared to controls, turdigity was maintained. The steroids stimulated rooting, but inhibited K+ uptake by roots and shoots. Ca2+ concentrations were high in roots grown with steroids. Treated plants were slightly chlorotic, but concentrations of Fe2+ were high in roots and shoots. The effects of the steroids on the plants were similar to those reported for animals. Evidently, stomatal closure caused by the steroids might be due to inhibition of K2+ uptake, necessary for stomatal opening; high Ca2+ concentrations in the roots might promote cell division which results in formation of new roots, and the steroids may be used as antitranspirants.