Overview Fennel essential oil is used for various health aids such as the aid of constipation, digestive issues such as heartburn and bloating, and colic in infants. Common Uses Fennel oil is known to be very potent and should always be diluted before use. The strong aroma is also very overpowering in its raw form. It is suggested to add a few drops of the essential oil to boiled water and consume it. When giving it to infants, a very limited amount should be used each time. Fennel essential oil can also be used in baking of breads for the aroma. Recommended Storage The ideal storage of essential oils is to keep it refrigerated, as the fridge keeps the components that make up the oils at their optimal levels. If you don't have space in the fridge, you can keep it in a cool, dark place. Essential oils have a shelf life of one to five years. You should however replace essential oils after three years to gain the most benefits out of the essential oils.