Our study show that lorazepam calms the child very well before his operation, as long as a minimum dose of 0.04 mg/kg is administered; if one wishes to increase the chances of provoking complete or incomplete amnesia, the dose must be increased to 0.05 mg/kg, administering a dose of 0.06 mg/kg does not increase the percentage of amnesia but provoked a side effect which is not very agreeable from the point of view of nursing and one to which our anesthetics technique has not accustomed us: sleepiness. Lastly the pre-operatory vomitting being almost certainly linked with the administration per os, an effort should be made to improve the presentation, so keeping the advantages of premedication without giving an injection to the child; furthermore as far as possible, the presentation should permit a sufficiently precise evaluation of the quantity to be administered, even though slight errors are here of no consequence due to the very large margin of security.