Having reviewed what is known, what is only surmised, and what is not known about the psychopharmacology of stimulant drug use in children, the clinician must decide for which patient to use what drug for how long. Medical practice does not permit the physician the luxury of deferring decisions until knowledge is certain. His task is to weigh putative benefits against putative risks in a strategy designed to maximize the probability of improvement for a particular patient. The risks that concern the pediatrician are not only those visible in the short run during drug administration but include effects on development, effects which may not become apparent for some time after treatment has been discontinued. In the case of stimulant drugs, public controversy has centered on behavioral rather than pharmacological toxicity, both short and long run. In the short run, are the drugs being used indiscriminately to stifle independence and creativity among exceptional children? Over the long run, does childhood drug use predispose to adolescent drug addiction? Before attempting to answer these questions, let us first consider the medical indications for the use of stimulants and the mode of their administration. The clinical syndromes which respond to stimulants are characterized by motor restlessness, short attention span, poor impulse control, learning difficulties, and emotional lability. Current American Psychiatric Association diagnostic nomenclature1 includes the term: "hyperkinetic reaction of childhood" to describe this set of symptoms; the World Health Organization2 is proposing: "hyperkinetic syndrome." Both terms have the virtue of stressing the symptom constellation and of by-passing the uncertainties surrounding cause.