In ancient Chinese, Roman, Greek, and Egyptian remedies, fennel is a commonly used herb. Fennel essential oil, as the result of its powerful constituents, offers a number of health and beauty benefits, which is why it remains a favorite of aromatherapists centuries later. One of fennel essential oil’s main active ingredients, anethole, is largely responsible for the health benefits fennel offers.
Anethole is responsible for as much as 80.2% of fennel essential oil’s chemical makeup. Multiple researchers have found that anethole, a volatile oil, can significantly improve the symptoms experienced with digestive system issues, including constipation, abdominal cramping, chronic gas, and bloating . As a volatile oil, it quickly evaporates into a vapor form in the body, which provides symptom relief and improves motility quickly. In addition to providing relief for adults, it is considered a very safe and effective method for treating colic in infants.
Additionally, anethole has shown to play a key role in killing cancer cells, decreasing tumors, and increasing the survival time of cancer patients, particularly those suffering from lung, colon, and breast cancer . It does this by preventing tumor necrosis factor (TNF)-mediated signaling, which promotes tumor growth, from activating in the body.
Anethole also has been shown to have anti-inflammatory properties that helps reduces swelling, pain, and redness associated with both chronic conditions, such as osteoarthritis, and acute conditions, such as a muscle sprain . This is related to anethole’s ability to impede the production of NF-kappa B cells, which is known for stimulating inflammation related to a variety of conditions, including asthma and allergies.
 http://www.sciencedirect.com/science/article/pii/S1878535212000792  http://4healthykids.com/treating-colic-with-fennel/  http://www.naturalhealth365.com/cancer-cell-growth-spices-1111.html/