In order to examine whether the anabolic steroid oxandrolone has any long-term effect on height in Turner syndrome, the short- and long-term effects were studied in a group of 35 individuals with the syndrome. At commencement of treatment, age range was 8.2-16 years (mean 12.9); oxandrolone dosage was 0.07-0.26 mg/kg per day (mean 0.14 mg/kg per day) and continued for 12 months-6 years (mean 33 months), ending at 12-18.5 years (mean 15.6 years). Height velocity increased significantly on therapy from 3.3 +/- 0.1 to 5.8 +/- 0.3 cm/year at 6 and 12 months, and maintained at 4.8 +/- 0.3 cm/year by two years (all P less than 0.001). Girls who were younger and whose bone age was delayed grew faster (P less than 0.001). Oxandrolone dose correlated with height velocity at 12 (r = 0.39, P less than 0.05) and 18 months (r = 0.31, P less than 0.05). Both height standard deviation score (SDS) and estimated mature height (EMH) increased significantly by the end of treatment (-0.31 +/- 0.2 to 0.45 +/- 0.2, and 140.4 +/- 1.1 cm to 144.4 +/- 1.1 cm respectively (both P less than 0.0001). In 23 patients who had completed growth at a mean age of 20.6 +/- 0.83 years, final height was 145.5 +/- 1.3 cm. This was not significantly different from EMH of 144.9 +/- 1.3 cm at the end of therapy, and based on a pre-treatment EMH of 140.5 +/- 1.3 cm, represented a mean height gain of 5 cm.(ABSTRACT TRUNCATED AT 250 WORDS)