Urinary dehydroepiandrosterone sulphate (DHAS) concentration was measured as DHA in 100 non-obese females with idiopathic hirsutism, while, at the same time, a similar number of normal males and normal females, of comparable age group and with normal body weight, were also included in this study. The method applied involved hydrolysis of DHA-sulphate conjugate after boiling the urine samples, followed by ether extraction of the free steroid, evaporation of ether, Girard T separation of ketones from non-ketones, paper chromatographic separation of DHAS from 6beta-hydroxy-3,5-cycloandrostan-17-one and, finally DHAS was estimated spectrophotometrically after Zimmermann reaction. For comparison, 30 urine samples were estimated by a g.l.c. procedure and good agreement was found with the spectrophotometric method. It was necessary to purify DHAS by paper chromatography before Zimmerman reaction was carried out as, in the same 30 urine samples, DHAS was consistently being overestimated. Urinary DHAS (mg/24 h) in normal males gave a mean of: 2.5+/-0.94 (SD), range: 0.35+/-4.8; in normal females, mean: 1.3+/-0.57 (SD), range: 0.28-2.6; in hirsute females, mean: 2.1+/-1.5 (SD), range: 0.65-9.7. Of these hirsute females, 26 were above the range found in normal women and mean values were higher than those from the same number of normal females of comparable age group; this was found to be significant (P less than 0.0005). These results indicate that urinary DHAS (as DHA) estimation in women with idiopathic hirsutism is clinically useful and could be applied as an index of androgen status in these women.