What is fennel? How can I use this feathery, bulb plant? Fennel is actually one of the few vegetables that the entire plant is edible. It has a distinct licorice flavor and is not only used for cooking but nutritionally as well. Fennel contains almost 20% of your daily recommended dose of Vitamin C. Other vitamins and minerals include potassium, an electrolyte that fights high blood pressure, and folate, which protects against potentially dangerous molecules. Fennel seed oil has a nutrient in it called antethole… this nutrient has been known to help against cancer occurrence “possibly due to a biological mechanism that shuts down or prevents the activation of NF-kappaB, a gene-altering, inflammation-triggering molecule.” Check out all the health benefits of fennel below.