Children with overanxious and/or avoidant disorder (DSM-III) were treated with alprazolam (Xanax, Upjohn) to determine its safety, clinical and cognitive effects. Ten male and two female patients (age range 8.8 to 16.5 years; mean 11.5) participated in an open clinical trial consisting of a baseline placebo period (1 week), alprazolam therapy (4 weeks), a drug-tapering period (1 week), and a post-drug placebo period (1 week). There was a drug-free follow-up approximately 4 weeks after termination of the study. Dosages were individually adjusted and the daily maximum ranged from 0.50 mg to 1.5 mg. Evaluations included clinical assessments, parent, teacher and self ratings, and cognitive tests. Clinical global improvement with alprazolam therapy was marked in 1 patient, moderate in 6, minimal in 4, and none in 1. Clinician ratings indicated significant improvements of anxiety, depression, and psychomotor excitation. Parent questionnaires indicated significant improvements of anxiety and hyperactivity while teacher questionnaires showed significant improvement of an anxious-passive factor. Significant improvements in the paired associate learning tasks, maze task and the block design tasks were maintained after drug withdrawal suggesting a practice effect. Adverse effects were infrequent, mild and transient. There were no clinically significant changes of laboratory values, blood pressure, pulse or respiration during the 4 weeks of alprazolam administration. Body weight increased significantly (mean increase was 0.87 kg). Double-blind trials with alprazolam are recommended in child psychiatry disorders.