Fennel the spice is legal. You can grind it to a powder for recipes. Once you see improvements you can use it crushed.
Fennel the vegetable is legal but it is very fibrous. It should only be used by those with significant improvements.
Elaine wrote this about Fennel the veggie: "Fresh fennel is similar to celery and is OK. It is very fibrous and only those who are practically without symptoms should eat all that fiber. If people already have a narrowing at the ileum, these stringy and very fibrous foods can plug them up further." from