The important results of this experiment can be summarized as follows:Both growth regulators increased significantly the total seed yield per plant and B-9 proved to be more effective in this respect.Both growth regulators increased significantly the essential oil yield per plant and no significant difference between the two regulators was found in this respect.Ethrel had no effect on the content of anethole  but decreased significantly the contact of fenchone in the essential oil comparing with the untreated plants.B-9 increased the content of anethole and decreased considerably the content of fenchone. Generally, B-9 is superior and the most suitable compound for improving the essential oil quality since it increased the anethole and decreased the fenchone content of the oil.