Objective        To compare melatonin with chloral hydrate in inducing sleep in children undergoing electroencephalography (EEG) in order to find a safe drug with no effect on brain wave when inducing sleep for sleep EEG in uncooperative children.       Methods        A total of 206 uncooperative children who undergoing EEG in our hospital during January 2010 to September 2011 were randomly divided into melatonin group (n=109) and chloral hydrate group (n=97) after the approval of Ethics Committee of our hospital and consents of their parents. All the children took melatonin or chloral hydrate in 0.5 h before the examination. The diagnosis

sleep latency

sleep duration

sleepy time

EEG wave background

and medication adverse reactions were recorded and analyzed.       Results        Melatonin successfully induced sleep in 83 cases

accounting for 76.1%

while chloral hydrate in 87 cases

accounting for 89.7% (P0.05). There was no significant difference in the sleep latency for hypnotized children between the 2 groups

but the sleep duration and sleepy time was shorter in melatonin group than chloral hydrate group (Mann-Whitney test

P0.05). Chloral hydrate increased β fast wave in 16 cases (18.4%)

and melatonin increased β fast wave in 5 cases (6.0%

Mann-Whitney test

P0.05). There were 16 children in chloral hydrate group having vomiting

1 child with uncoordinated gait

while only 4 cases in melatonin group were excited. No other adverse reaction was found.       Conclusion        Though the success rate for sleep inducement is lower when using melatonin than chloral hydrate

but melatonin has shorter sleep duration and sleepy time

and less effect on brain waves

and lesser adverse reactions. It is recommended to induce sleep EEG in uncooperative children.