To evaluate the efficacy and safety of intranasal midazolam in the treatment of autonomic crises in children with familial dysautonomia, intranasal midazolam was administered at the hospital to six patients during nine episodes of autonomic crisis. Treatment was successful in seven of nine episodes of autonomic crisis in five of six patients, with a mean interval to response of 9.25 +/- 1.25 minutes. The parents of five patients in whom the treatment was successful were instructed to use midazolam at home. At home, 16 additional episodes were treated by the parents, with successful control achieved in 14 (87%). The mean interval to response was 12.8 +/- 2 minutes. No significant side effects were observed at the hospital or at home after intranasal administration of midazolam. Midazolam, given intranasally, is effective and safe in the management of autonomic crises in patients with familial dysautonomia, either in the hospital or at home by the parents after appropriate instruction.