Fennel is a medicinal and aromatic plant with a diverse pharmacological spectrum and having considerable importance in particular to food industry. Its aroma active compounds such as anethole (and its polymers like dianethole and photoanethole) estragole, (+)-Fenchone and P-anisaldehyde have been recognised as the biologically active molecules possessing oestrogenic, acaricidal and antithrombotic activities. The phenolic molecules present in fennel have been shown to possess potent antioxidant activity in a number of experiments. These bioactive molecules in fennel can be developed as novel pharmacological lead molecules provided their bioavailability, pharmacokinetics, physiological pathways, and importance to human health are known with sufficient detail.