Cocaine and its principal metabolite, benzoyl ecgonine, were isolated from the urine of four hospitalized children who had been exposed to the smoke of freebase cocaine ("crack") used by their adult caretakers. Two of the children had transient neurological symptoms (drowsiness and unsteady gait) and two had seizures whose cause could not be determined by laboratory investigation. Passive cocaine inhalation may have caused or contributed to these symptoms. Children in the care of adults who abuse freebase cocaine should be considered at risk not only for disruption of their social environment but also for the effects of cocaine toxicity.