In a clinical trial, efficacy and safety of promethazine and chloral hydrate in induction of sedation of 60 children 1-18 years old referred to electroencephalography unit, will be evaluated. The patients will randomly be assigned to receive either 100 mg/kg/dose of chloral hydrate or 1mg/kg promethazine until Ramsay score of four is attained. If the child is not sedated after 30 minutes of drug use, the second dose of drug in half of the first dose will be administered. Vital signs, level of consciousness, cyanosis, respiratory state, vomiting, dystonia, and extra pyramidal adverse effect will be evaluated in children for two hours after drug use. Efficacy of drugs in sedation induction, time to induction of sedation, total stay time in EEG unit, serious adverse events (hypotension, hypoxia and cyanosis, severe vomiting, irritability, apnea, laryngospasm, and bradycardia), and caregiver’s satisfaction are also compared between groups.