Fennel is a great spice for seasoning seafood and pork. It is primarily used in French and Italian cuisine, bringing a unique flavor to many dishes. It also makes up one fifth of the Chinese Five Spices.
Fennel has served medicinal purposes over the centuries. In Renaissance Europe, it was used as an appetite suppressant. In India, it was used as a snakebite remedy.
Here's a fun fact: it was popular among Puritans to chew fennel seeds to suppress hunger during long church meetings. Incidentally...in high doses, fennel causes hallucinations and muscle spasms.