Agent for lowering prolactin

A prolactin lowering drug comprising at least one bicyclic diterpene compound of the clerodane type in accordance with at least one of general formulae (III) or (IV):

• wherein R1=H, C1 to C3 alkyl or C1 to C3 acyl;
• wherein the rings A and/or B in the case of general formulae (III) or (IV) are optionally substituted in position 1, 2, 3, 4, 6, 7, or 8 with at least one OX radical, with X=H, C1 to C3 alkyl or C1 to C3 acyl;
• wherein optionally at least one carbon atom in position 17, 18, 19 and 20 is substituted with an OX radical, with X=H, C1 to C3 alkyl or C1 to C3 acyl;
• wherein optionally at least one CH3 group in position 17, 18, 19 and 20 is replaced by one COOH group;
• wherein optionally at least one of ring positions 1, 2, 3, 6, or 7 is a keto group;
• and
• wherein optionally at least one double bond is present in ring positions 1, 2, 3, 6, 7, 8, 8(17) of formula (III);
• and
• wherein optionally at least one double bond is present in ring positions 1, 2, 3, 4(18), 6, 7, 8, 8(17) of formula (IV);
• with the exception of the following compounds:
• (+) hardwickiic acid, crolechinic acid, and hautriwaic acid.