Fifteen girls and five boys with excessive predicted adult height (chronological age, 10.1-14.6 yr; bone age, 11.0-14.0 yr) were treated with bromocriptine (two doses; 2.5 mg/day) to reduce their final height. After a mean treatment period of 1.14 yr (range, 0.6-1.75 yr) we did not find a reduction of predicted adult height [difference, -0.5 +/- 3.5 (+/- SD) cm according to Bayley and Pinneau's tables (P = NS) and +0.2 +/- 2.5 (+/- SD) cm according to the method of Tanner (P = NS)]. Mean peak plasma GH concentrations after TRH administration before and during bromocriptine were 51.5 +/- 49.4 and 58.5 +/- 50.7 mU/L, respectively. The wide range of the GH values may be explained by physiological variation in this age group. After ingestion of 2.5 mg bromocriptine a significant increase in plasma GH occurred within 3 h in six adolescents tested. Our results do not support the concept that bromocriptine may reduce predicted adult height in tall adolescents by decreased GH secretion or acceleration of skeletal maturation.