The present invention relates to the use of a Eucalyptus for preparation of a drug or a dietary supplement intended for treatment and/or prevention of affections or pathologies caused by neuromediator recapture disorder. The present invention also relates to a new enriched extract of Eucalyptus characterized in that it contains at least one compound having the formula (I) or any one of its diastereoisomers in which R1 forms a C.dbd.CH2 substituent with the carbon to which it is joined, a formula (II) substituent and R2 which represents an isobutyl, .alpha.-isobutyl or .beta.-isobutyl substituent; and the method of preparation thereof. ##STR00001##