Italian sausage comes in sweet or hot varieties.  A few spices but the primary flavor comes from the fennel seed.  Stuffed into a casing is great but like any sausage feel free to leave it as is and use it on a sandwich with some sautéed peppers and onions or rolled into meatballs for pasta or a hoagie or even in your lasagna as a substitute for ground beef.  One of our favorites.  Adjust the heat to your liking.